diff --git a/CHANGES/10600.bugfix.rst b/CHANGES/10600.bugfix.rst
new file mode 100644
index 00000000000..eba47bf56e6
--- /dev/null
+++ b/CHANGES/10600.bugfix.rst
@@ -0,0 +1,2 @@
+Fixed http parser not rejecting HTTP/1.1 requests that do not have valid Host header.
+-- by :user:`Cycloctane`.
diff --git a/aiohttp/_http_parser.pyx b/aiohttp/_http_parser.pyx
index 2f528117b1c..245d16d27e3 100644
--- a/aiohttp/_http_parser.pyx
+++ b/aiohttp/_http_parser.pyx
@@ -437,6 +437,7 @@ cdef class HttpParser:
     cdef _on_headers_complete(self):
         self._process_header()
 
+        http_version = self.http_version()
         should_close = not cparser.llhttp_should_keep_alive(self._cparser)
         upgrade = self._cparser.upgrade
         chunked = self._cparser.flags & cparser.F_CHUNKED
@@ -453,6 +454,8 @@ cdef class HttpParser:
             raise BadHttpMessage(f"Duplicate '{bad_hdr}' header found.")
 
         if self._cparser.type == cparser.HTTP_REQUEST:
+            if http_version == HttpVersion11 and hdrs.HOST not in headers:
+                raise BadHttpMessage("Missing 'Host' header in request.")
             h_upg = headers.get("upgrade", "")
             allowed = upgrade and h_upg.isascii() and h_upg.lower() in ALLOWED_UPGRADES
             if allowed or self._cparser.method == cparser.HTTP_CONNECT:
@@ -476,11 +479,11 @@ cdef class HttpParser:
             method = http_method_str(self._cparser.method)
             msg = _new_request_message(
                 method, self._path,
-                self.http_version(), headers, raw_headers,
+                http_version, headers, raw_headers,
                 should_close, encoding, upgrade, chunked, self._url)
         else:
             msg = _new_response_message(
-                self.http_version(), self._cparser.status_code, self._reason,
+                http_version, self._cparser.status_code, self._reason,
                 headers, raw_headers, should_close, encoding,
                 upgrade, chunked)
 
diff --git a/aiohttp/http_parser.py b/aiohttp/http_parser.py
index d0aee4d75c4..be638f1f965 100644
--- a/aiohttp/http_parser.py
+++ b/aiohttp/http_parser.py
@@ -41,7 +41,7 @@
     LineTooLong,
     TransferEncodingError,
 )
-from .http_writer import HttpVersion, HttpVersion10
+from .http_writer import HttpVersion, HttpVersion10, HttpVersion11
 from .streams import EMPTY_PAYLOAD, StreamReader
 from .typedefs import RawHeaders
 
@@ -635,6 +635,9 @@ def parse_message(self, lines: list[bytes]) -> RawRequestMessage:
             chunked,
         ) = self.parse_headers(lines[1:])
 
+        if version_o == HttpVersion11 and hdrs.HOST not in headers:
+            raise BadHttpMessage("Missing 'Host' header in request.")
+
         if close is None:  # then the headers weren't set in the request
             if version_o <= HttpVersion10:  # HTTP 1.0 must asks to not close
                 close = True
diff --git a/tests/test_http_parser.py b/tests/test_http_parser.py
index 1bf80d271c3..2b647d69149 100644
--- a/tests/test_http_parser.py
+++ b/tests/test_http_parser.py
@@ -125,6 +125,7 @@ def test_c_parser_loaded() -> None:
 
 def test_parse_headers(parser: HttpRequestParser) -> None:
     text = b"""GET /test HTTP/1.1\r
+Host: a\r
 test: a line\r
 test2: data\r
 \r
@@ -133,8 +134,16 @@ def test_parse_headers(parser: HttpRequestParser) -> None:
     assert len(messages) == 1
     msg = messages[0][0]
 
-    assert list(msg.headers.items()) == [("test", "a line"), ("test2", "data")]
-    assert msg.raw_headers == ((b"test", b"a line"), (b"test2", b"data"))
+    assert list(msg.headers.items()) == [
+        ("Host", "a"),
+        ("test", "a line"),
+        ("test2", "data"),
+    ]
+    assert msg.raw_headers == (
+        (b"Host", b"a"),
+        (b"test", b"a line"),
+        (b"test2", b"data"),
+    )
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -142,6 +151,7 @@ def test_parse_headers(parser: HttpRequestParser) -> None:
 
 def test_reject_obsolete_line_folding(parser: HttpRequestParser) -> None:
     text = b"""GET /test HTTP/1.1\r
+Host: a\r
 test: line\r
  Content-Length: 48\r
 test2: data\r
@@ -208,7 +218,7 @@ def test_cve_2023_37276(parser: HttpRequestParser) -> None:
 def test_bad_header_name(
     parser: HttpRequestParser, rfc9110_5_6_2_token_delim: str
 ) -> None:
-    text = f"POST / HTTP/1.1\r\nhead{rfc9110_5_6_2_token_delim}er: val\r\n\r\n".encode()
+    text = f"POST / HTTP/1.1\r\nHost: a\r\nhead{rfc9110_5_6_2_token_delim}er: val\r\n\r\n".encode()
     if rfc9110_5_6_2_token_delim == ":":
         # Inserting colon into header just splits name/value earlier.
         parser.feed_data(text)
@@ -237,7 +247,7 @@ def test_bad_header_name(
     ),
 )
 def test_bad_headers(parser: HttpRequestParser, hdr: str) -> None:
-    text = f"POST / HTTP/1.1\r\n{hdr}\r\n\r\n".encode()
+    text = f"POST / HTTP/1.1\r\nHost: a\r\n{hdr}\r\n\r\n".encode()
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
 
@@ -259,7 +269,7 @@ def test_unpaired_surrogate_in_header_py(
         max_line_size=8190,
         max_field_size=8190,
     )
-    text = b"POST / HTTP/1.1\r\n\xff\r\n\r\n"
+    text = b"POST / HTTP/1.1\r\nHost: a\r\n\xff\r\n\r\n"
     message = None
     try:
         parser.feed_data(text)
@@ -318,6 +328,12 @@ def test_duplicate_host_header_rejected(parser: HttpRequestParser) -> None:
         parser.feed_data(text)
 
 
+def test_missing_host_header_rejected(parser: HttpRequestParser) -> None:
+    text = b"GET /admin HTTP/1.1\r\n\r\n"
+    with pytest.raises(http_exceptions.BadHttpMessage, match="Missing 'Host' header"):
+        parser.feed_data(text)
+
+
 def test_bad_chunked(parser: HttpRequestParser) -> None:
     """Test that invalid chunked encoding doesn't allow content-length to be used."""
     text = (
@@ -329,7 +345,7 @@ def test_bad_chunked(parser: HttpRequestParser) -> None:
 
 
 def test_whitespace_before_header(parser: HttpRequestParser) -> None:
-    text = b"GET / HTTP/1.1\r\n\tContent-Length: 1\r\n\r\nX"
+    text = b"GET / HTTP/1.1\r\nHost: a\r\n\tContent-Length: 1\r\n\r\nX"
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
 
@@ -360,7 +376,7 @@ def test_parse_unusual_request_line(parser: HttpRequestParser) -> None:
 
 
 def test_parse(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     assert len(messages) == 1
     msg, _ = messages[0]
@@ -369,10 +385,11 @@ def test_parse(parser: HttpRequestParser) -> None:
     assert msg.method == "GET"
     assert msg.path == "/test"
     assert msg.version == (1, 1)
+    assert msg.headers["Host"] == "a"
 
 
 async def test_parse_body(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nContent-Length: 4\r\n\r\nbody"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nContent-Length: 4\r\n\r\nbody"
     messages, upgrade, tail = parser.feed_data(text)
     assert len(messages) == 1
     _, payload = messages[0]
@@ -381,7 +398,7 @@ async def test_parse_body(parser: HttpRequestParser) -> None:
 
 
 async def test_parse_body_with_CRLF(parser: HttpRequestParser) -> None:
-    text = b"\r\nGET /test HTTP/1.1\r\nContent-Length: 4\r\n\r\nbody"
+    text = b"\r\nGET /test HTTP/1.1\r\nHost: a\r\nContent-Length: 4\r\n\r\nbody"
     messages, upgrade, tail = parser.feed_data(text)
     assert len(messages) == 1
     _, payload = messages[0]
@@ -390,7 +407,7 @@ async def test_parse_body_with_CRLF(parser: HttpRequestParser) -> None:
 
 
 def test_parse_delayed(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     assert len(messages) == 0
     assert not upgrade
@@ -403,8 +420,9 @@ def test_parse_delayed(parser: HttpRequestParser) -> None:
 
 def test_headers_multi_feed(parser: HttpRequestParser) -> None:
     text1 = b"GET /test HTTP/1.1\r\n"
-    text2 = b"test: line"
-    text3 = b" continue\r\n\r\n"
+    text2 = b"Host: a\r\n"
+    text3 = b"test: line"
+    text4 = b" continue\r\n\r\n"
 
     messages, upgrade, tail = parser.feed_data(text1)
     assert len(messages) == 0
@@ -413,18 +431,21 @@ def test_headers_multi_feed(parser: HttpRequestParser) -> None:
     assert len(messages) == 0
 
     messages, upgrade, tail = parser.feed_data(text3)
+    assert len(messages) == 0
+
+    messages, upgrade, tail = parser.feed_data(text4)
     assert len(messages) == 1
 
     msg = messages[0][0]
-    assert list(msg.headers.items()) == [("test", "line continue")]
-    assert msg.raw_headers == ((b"test", b"line continue"),)
+    assert list(msg.headers.items()) == [("Host", "a"), ("test", "line continue")]
+    assert msg.raw_headers == ((b"Host", b"a"), (b"test", b"line continue"))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
 
 
 def test_headers_split_field(parser: HttpRequestParser) -> None:
-    text1 = b"GET /test HTTP/1.1\r\n"
+    text1 = b"GET /test HTTP/1.1\r\nHost: a\r\n"
     text2 = b"t"
     text3 = b"es"
     text4 = b"t: value\r\n\r\n"
@@ -437,8 +458,8 @@ def test_headers_split_field(parser: HttpRequestParser) -> None:
     assert len(messages) == 1
 
     msg = messages[0][0]
-    assert list(msg.headers.items()) == [("test", "value")]
-    assert msg.raw_headers == ((b"test", b"value"),)
+    assert list(msg.headers.items()) == [("Host", "a"), ("test", "value")]
+    assert msg.raw_headers == ((b"Host", b"a"), (b"test", b"value"))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -446,7 +467,7 @@ def test_headers_split_field(parser: HttpRequestParser) -> None:
 
 def test_parse_headers_multi(parser: HttpRequestParser) -> None:
     text = (
-        b"GET /test HTTP/1.1\r\n"
+        b"GET /test HTTP/1.1\r\nHost: a\r\n"
         b"Set-Cookie: c1=cookie1\r\n"
         b"Set-Cookie: c2=cookie2\r\n\r\n"
     )
@@ -456,10 +477,12 @@ def test_parse_headers_multi(parser: HttpRequestParser) -> None:
     msg = messages[0][0]
 
     assert list(msg.headers.items()) == [
+        ("Host", "a"),
         ("Set-Cookie", "c1=cookie1"),
         ("Set-Cookie", "c2=cookie2"),
     ]
     assert msg.raw_headers == (
+        (b"Host", b"a"),
         (b"Set-Cookie", b"c1=cookie1"),
         (b"Set-Cookie", b"c2=cookie2"),
     )
@@ -475,14 +498,14 @@ def test_conn_default_1_0(parser: HttpRequestParser) -> None:
 
 
 def test_conn_default_1_1(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert not msg.should_close
 
 
 def test_conn_close(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nconnection: close\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nconnection: close\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.should_close
@@ -503,14 +526,14 @@ def test_conn_keep_alive_1_0(parser: HttpRequestParser) -> None:
 
 
 def test_conn_keep_alive_1_1(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nconnection: keep-alive\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nconnection: keep-alive\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert not msg.should_close
 
 
 def test_conn_close_comma_list(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nconnection: close, keep-alive\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nconnection: close, keep-alive\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.should_close
@@ -519,6 +542,7 @@ def test_conn_close_comma_list(parser: HttpRequestParser) -> None:
 def test_conn_close_multiple_headers(parser: HttpRequestParser) -> None:
     text = (
         b"GET /test HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"connection: keep-alive\r\n"
         b"connection: close\r\n\r\n"
     )
@@ -535,14 +559,14 @@ def test_conn_other_1_0(parser: HttpRequestParser) -> None:
 
 
 def test_conn_other_1_1(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nconnection: test\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nconnection: test\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert not msg.should_close
 
 
 def test_request_chunked(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntransfer-encoding: chunked\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntransfer-encoding: chunked\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg, payload = messages[0]
     assert msg.chunked
@@ -552,14 +576,14 @@ def test_request_chunked(parser: HttpRequestParser) -> None:
 
 def test_te_header_non_ascii(parser: HttpRequestParser) -> None:
     # K = Kelvin sign, not valid ascii.
-    text = "GET /test HTTP/1.1\r\nTransfer-Encoding: chunKed\r\n\r\n"
+    text = "GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: chunKed\r\n\r\n"
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text.encode())
 
 
 def test_upgrade_header_non_ascii(parser: HttpRequestParser) -> None:
     # K = Kelvin sign, not valid ascii.
-    text = "GET /test HTTP/1.1\r\nUpgrade: websocKet\r\n\r\n"
+    text = "GET /test HTTP/1.1\r\nHost: a\r\nUpgrade: websocKet\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text.encode())
     assert not upgrade
 
@@ -567,6 +591,7 @@ def test_upgrade_header_non_ascii(parser: HttpRequestParser) -> None:
 def test_request_te_chunked_with_content_length(parser: HttpRequestParser) -> None:
     text = (
         b"GET /test HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"content-length: 1234\r\n"
         b"transfer-encoding: chunked\r\n\r\n"
     )
@@ -578,7 +603,7 @@ def test_request_te_chunked_with_content_length(parser: HttpRequestParser) -> No
 
 
 def test_request_te_chunked123(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntransfer-encoding: chunked123\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntransfer-encoding: chunked123\r\n\r\n"
     with pytest.raises(
         http_exceptions.BadHttpMessage,
         match="Request has invalid `Transfer-Encoding`",
@@ -587,14 +612,14 @@ def test_request_te_chunked123(parser: HttpRequestParser) -> None:
 
 
 async def test_request_te_last_chunked(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nTransfer-Encoding: not, chunked\r\n\r\n1\r\nT\r\n3\r\nest\r\n0\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: not, chunked\r\n\r\n1\r\nT\r\n3\r\nest\r\n0\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     # https://www.rfc-editor.org/rfc/rfc9112#section-6.3-2.4.3
     assert await messages[0][1].read() == b"Test"
 
 
 def test_request_te_first_chunked(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nTransfer-Encoding: chunked, not\r\n\r\n1\r\nT\r\n3\r\nest\r\n0\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: chunked, not\r\n\r\n1\r\nT\r\n3\r\nest\r\n0\r\n\r\n"
     # https://www.rfc-editor.org/rfc/rfc9112#section-6.3-2.4.3
     with pytest.raises(
         http_exceptions.BadHttpMessage,
@@ -617,6 +642,7 @@ def test_request_te_duplicate_chunked(parser: HttpRequestParser) -> None:
 def test_conn_upgrade(parser: HttpRequestParser) -> None:
     text = (
         b"GET /test HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"connection: upgrade\r\n"
         b"upgrade: websocket\r\n\r\n"
     )
@@ -630,6 +656,7 @@ def test_conn_upgrade(parser: HttpRequestParser) -> None:
 def test_conn_upgrade_comma_list(parser: HttpRequestParser) -> None:
     text = (
         b"GET /test HTTP/1.1\r\n"
+        b"host: a\r\n"
         b"connection: keep-alive, upgrade\r\n"
         b"upgrade: websocket\r\n\r\n"
     )
@@ -643,6 +670,7 @@ def test_conn_upgrade_comma_list(parser: HttpRequestParser) -> None:
 def test_conn_upgrade_multiple_headers(parser: HttpRequestParser) -> None:
     text = (
         b"GET /test HTTP/1.1\r\n"
+        b"host: a\r\n"
         b"connection: keep-alive\r\n"
         b"connection: upgrade\r\n"
         b"upgrade: websocket\r\n\r\n"
@@ -656,7 +684,7 @@ def test_conn_upgrade_multiple_headers(parser: HttpRequestParser) -> None:
 
 def test_bad_upgrade(parser: HttpRequestParser) -> None:
     """Test not upgraded if missing Upgrade header."""
-    text = b"GET /test HTTP/1.1\r\nconnection: upgrade\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nconnection: upgrade\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert not msg.upgrade
@@ -664,21 +692,21 @@ def test_bad_upgrade(parser: HttpRequestParser) -> None:
 
 
 def test_compression_empty(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: \r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: \r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.compression is None
 
 
 def test_compression_deflate(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: deflate\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: deflate\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.compression == "deflate"
 
 
 def test_compression_gzip(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: gzip\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: gzip\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.compression == "gzip"
@@ -686,7 +714,7 @@ def test_compression_gzip(parser: HttpRequestParser) -> None:
 
 @pytest.mark.skipif(brotli is None, reason="brotli is not installed")
 def test_compression_brotli(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: br\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: br\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.compression == "br"
@@ -694,7 +722,7 @@ def test_compression_brotli(parser: HttpRequestParser) -> None:
 
 @pytest.mark.skipif(zstandard is None, reason="zstandard is not installed")
 def test_compression_zstd(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: zstd\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: zstd\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.compression == "zstd"
@@ -708,7 +736,7 @@ def test_compression_zstd(parser: HttpRequestParser) -> None:
     ),
 )
 def test_compression_non_ascii(parser: HttpRequestParser, enc: bytes) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: " + enc + b"\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: " + enc + b"\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     # Non-ascii input should not evaluate to a valid encoding scheme.
@@ -716,14 +744,14 @@ def test_compression_non_ascii(parser: HttpRequestParser, enc: bytes) -> None:
 
 
 def test_compression_unknown(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-encoding: compress\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-encoding: compress\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.compression is None
 
 
 def test_url_connect(parser: HttpRequestParser) -> None:
-    text = b"CONNECT www.google.com HTTP/1.1\r\ncontent-length: 0\r\n\r\n"
+    text = b"CONNECT www.google.com HTTP/1.1\r\nHost: a\r\ncontent-length: 0\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg, payload = messages[0]
     assert upgrade
@@ -731,7 +759,7 @@ def test_url_connect(parser: HttpRequestParser) -> None:
 
 
 def test_headers_connect(parser: HttpRequestParser) -> None:
-    text = b"CONNECT www.google.com HTTP/1.1\r\ncontent-length: 0\r\n\r\n"
+    text = b"CONNECT www.google.com HTTP/1.1\r\nHost: a\r\ncontent-length: 0\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg, payload = messages[0]
     assert upgrade
@@ -741,6 +769,7 @@ def test_headers_connect(parser: HttpRequestParser) -> None:
 def test_url_absolute(parser: HttpRequestParser) -> None:
     text = (
         b"GET https://www.google.com/path/to.html HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"content-length: 0\r\n\r\n"
     )
     messages, upgrade, tail = parser.feed_data(text)
@@ -751,21 +780,21 @@ def test_url_absolute(parser: HttpRequestParser) -> None:
 
 
 def test_headers_old_websocket_key1(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nSEC-WEBSOCKET-KEY1: line\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nSEC-WEBSOCKET-KEY1: line\r\n\r\n"
 
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
 
 
 def test_headers_content_length_err_1(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-length: line\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-length: line\r\n\r\n"
 
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
 
 
 def test_headers_content_length_err_2(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ncontent-length: -1\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ncontent-length: -1\r\n\r\n"
 
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
@@ -790,7 +819,7 @@ def test_headers_content_length_err_2(parser: HttpRequestParser) -> None:
 def test_invalid_header_spacing(
     parser: HttpRequestParser, pad1: bytes, pad2: bytes, hdr: bytes
 ) -> None:
-    text = b"GET /test HTTP/1.1\r\n%s%s%s: value\r\n\r\n" % (pad1, hdr, pad2)
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\n%s%s%s: value\r\n\r\n" % (pad1, hdr, pad2)
     if pad1 == pad2 == b"" and hdr != b"":
         # one entry in param matrix is correct: non-empty name, not padded
         parser.feed_data(text)
@@ -801,19 +830,19 @@ def test_invalid_header_spacing(
 
 
 def test_empty_header_name(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\n:test\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\n:test\r\n\r\n"
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
 
 
 def test_invalid_header(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntest line\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntest line\r\n\r\n"
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
 
 
 def test_invalid_name(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntest[]: line\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntest[]: line\r\n\r\n"
 
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(text)
@@ -832,15 +861,15 @@ def test_max_header_field_size(parser: HttpRequestParser, size: int) -> None:
 
 def test_max_header_size_under_limit(parser: HttpRequestParser) -> None:
     name = b"t" * 8185
-    text = b"GET /test HTTP/1.1\r\n" + name + b":data\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\n" + name + b":data\r\n\r\n"
 
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.method == "GET"
     assert msg.path == "/test"
     assert msg.version == (1, 1)
-    assert msg.headers == CIMultiDict({name.decode(): "data"})
-    assert msg.raw_headers == ((name, b"data"),)
+    assert msg.headers == CIMultiDict([("Host", "a"), (name.decode(), "data")])
+    assert msg.raw_headers == ((b"Host", b"a"), (name, b"data"))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -872,7 +901,7 @@ def test_max_header_combined_size(parser: HttpRequestParser) -> None:
 async def test_max_trailer_size(parser: HttpRequestParser, size: int) -> None:
     value = b"t" * size
     text = (
-        b"GET /test HTTP/1.1\r\nTransfer-Encoding: chunked\r\n\r\n"
+        b"GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: chunked\r\n\r\n"
         + hex(4000)[2:].encode()
         + b"\r\n"
         + b"b" * 4000
@@ -898,7 +927,7 @@ async def test_max_headers(
     parser: HttpRequestParser, headers: int, trailers: int
 ) -> None:
     text = (
-        b"GET /test HTTP/1.1\r\nTransfer-Encoding: chunked"
+        b"GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: chunked"
         + b"".join(b"\r\nHeader-%d: Value" % i for i in range(headers))
         + b"\r\n\r\n4\r\ntest\r\n0"
         + b"".join(b"\r\nTrailer-%d: Value" % i for i in range(trailers))
@@ -914,15 +943,15 @@ async def test_max_headers(
 
 def test_max_header_value_size_under_limit(parser: HttpRequestParser) -> None:
     value = b"A" * 8185
-    text = b"GET /test HTTP/1.1\r\ndata:" + value + b"\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ndata:" + value + b"\r\n\r\n"
 
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
     assert msg.method == "GET"
     assert msg.path == "/test"
     assert msg.version == (1, 1)
-    assert msg.headers == CIMultiDict({"data": value.decode()})
-    assert msg.raw_headers == ((b"data", value),)
+    assert msg.headers == CIMultiDict([("Host", "a"), ("data", value.decode())])
+    assert msg.raw_headers == ((b"Host", b"a"), (b"data", value))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -963,15 +992,15 @@ def test_max_header_value_size_continuation_under_limit(
 
 
 def test_http_request_parser(parser: HttpRequestParser) -> None:
-    text = b"GET /path HTTP/1.1\r\n\r\n"
+    text = b"GET /path HTTP/1.1\r\nHost: a\r\n\r\n"
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
 
     assert msg.method == "GET"
     assert msg.path == "/path"
     assert msg.version == (1, 1)
-    assert msg.headers == CIMultiDict()
-    assert msg.raw_headers == ()
+    assert msg.headers == CIMultiDict({"Host": "a"})
+    assert msg.raw_headers == ((b"Host", b"a"),)
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -1002,7 +1031,7 @@ def test_http_request_bad_status_line(parser: HttpRequestParser) -> None:
 def test_http_request_bad_status_line_number(
     parser: HttpRequestParser, nonascii_digit: bytes
 ) -> None:
-    text = b"GET /digit HTTP/1." + nonascii_digit + b"\r\n\r\n"
+    text = b"GET /digit HTTP/1." + nonascii_digit + b"\r\nHost: a\r\n\r\n"
     with pytest.raises(http_exceptions.BadStatusLine):
         parser.feed_data(text)
 
@@ -1010,19 +1039,19 @@ def test_http_request_bad_status_line_number(
 def test_http_request_bad_status_line_separator(parser: HttpRequestParser) -> None:
     # single code point, old, multibyte NFKC, multibyte NFKD
     utf8sep = "\N{ARABIC LIGATURE SALLALLAHOU ALAYHE WASALLAM}".encode()
-    text = b"GET /ligature HTTP/1" + utf8sep + b"1\r\n\r\n"
+    text = b"GET /ligature HTTP/1" + utf8sep + b"1\r\nHost: a\r\n\r\n"
     with pytest.raises(http_exceptions.BadStatusLine):
         parser.feed_data(text)
 
 
 def test_http_request_bad_status_line_whitespace(parser: HttpRequestParser) -> None:
-    text = b"GET\n/path\fHTTP/1.1\r\n\r\n"
+    text = b"GET\n/path\fHTTP/1.1\r\nHost: a\r\n\r\n"
     with pytest.raises(http_exceptions.BadStatusLine):
         parser.feed_data(text)
 
 
 def test_http_request_message_after_close(parser: HttpRequestParser) -> None:
-    text = b"GET / HTTP/1.1\r\nConnection: close\r\n\r\nInvalid\r\n\r\n"
+    text = b"GET / HTTP/1.1\r\nHost: a\r\nConnection: close\r\n\r\nInvalid\r\n\r\n"
     with pytest.raises(
         http_exceptions.BadHttpMessage, match="Data after `Connection: close`"
     ):
@@ -1030,7 +1059,7 @@ def test_http_request_message_after_close(parser: HttpRequestParser) -> None:
 
 
 def test_http_request_message_after_close_comma_list(parser: HttpRequestParser) -> None:
-    text = b"GET / HTTP/1.1\r\nConnection: close, keep-alive\r\n\r\nInvalid\r\n\r\n"
+    text = b"GET / HTTP/1.1\r\nHost: a\r\nConnection: close, keep-alive\r\n\r\nInvalid\r\n\r\n"
     with pytest.raises(
         http_exceptions.BadHttpMessage, match="Data after `Connection: close`"
     ):
@@ -1040,6 +1069,7 @@ def test_http_request_message_after_close_comma_list(parser: HttpRequestParser)
 def test_http_request_upgrade(parser: HttpRequestParser) -> None:
     text = (
         b"GET /test HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"connection: upgrade\r\n"
         b"upgrade: websocket\r\n\r\n"
         b"some raw data"
@@ -1055,6 +1085,7 @@ def test_http_request_upgrade(parser: HttpRequestParser) -> None:
 async def test_http_request_upgrade_unknown(parser: HttpRequestParser) -> None:
     text = (
         b"POST / HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"Connection: Upgrade\r\n"
         b"Content-Length: 2\r\n"
         b"Upgrade: unknown\r\n"
@@ -1088,7 +1119,7 @@ def xfail_c_parser_url(request: pytest.FixtureRequest) -> None:
 def test_http_request_parser_utf8_request_line(parser: HttpRequestParser) -> None:
     messages, upgrade, tail = parser.feed_data(
         # note the truncated unicode sequence
-        b"GET /P\xc3\xbcnktchen\xa0\xef\xb7 HTTP/1.1\r\n" +
+        b"GET /P\xc3\xbcnktchen\xa0\xef\xb7 HTTP/1.1\r\nHost: a\r\n" +
         # for easier grep: ASCII 0xA0 more commonly known as non-breaking space
         # note the leading and trailing spaces
         "sTeP:  \N{LATIN SMALL LETTER SHARP S}nek\t\N{NO-BREAK SPACE}  "
@@ -1099,8 +1130,8 @@ def test_http_request_parser_utf8_request_line(parser: HttpRequestParser) -> Non
     assert msg.method == "GET"
     assert msg.path == "/Pünktchen\udca0\udcef\udcb7"
     assert msg.version == (1, 1)
-    assert msg.headers == CIMultiDict([("STEP", "ßnek\t\xa0")])
-    assert msg.raw_headers == ((b"sTeP", "ßnek\t\xa0".encode()),)
+    assert msg.headers == CIMultiDict([("Host", "a"), ("STEP", "ßnek\t\xa0")])
+    assert msg.raw_headers == ((b"Host", b"a"), (b"sTeP", "ßnek\t\xa0".encode()))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -1111,15 +1142,15 @@ def test_http_request_parser_utf8_request_line(parser: HttpRequestParser) -> Non
 
 
 def test_http_request_parser_utf8(parser: HttpRequestParser) -> None:
-    text = "GET /path HTTP/1.1\r\nx-test:тест\r\n\r\n".encode()
+    text = "GET /path HTTP/1.1\r\nHost: a\r\nx-test:тест\r\n\r\n".encode()
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
 
     assert msg.method == "GET"
     assert msg.path == "/path"
     assert msg.version == (1, 1)
-    assert msg.headers == CIMultiDict([("X-TEST", "тест")])
-    assert msg.raw_headers == ((b"x-test", "тест".encode()),)
+    assert msg.headers == CIMultiDict([("Host", "a"), ("X-TEST", "тест")])
+    assert msg.raw_headers == ((b"Host", b"a"), (b"x-test", "тест".encode()))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -1128,16 +1159,19 @@ def test_http_request_parser_utf8(parser: HttpRequestParser) -> None:
 
 
 def test_http_request_parser_non_utf8(parser: HttpRequestParser) -> None:
-    text = "GET /path HTTP/1.1\r\nx-test:тест\r\n\r\n".encode("cp1251")
+    text = "GET /path HTTP/1.1\r\nHost: a\r\nx-test:тест\r\n\r\n".encode("cp1251")
     msg = parser.feed_data(text)[0][0][0]
 
     assert msg.method == "GET"
     assert msg.path == "/path"
     assert msg.version == (1, 1)
     assert msg.headers == CIMultiDict(
-        [("X-TEST", "тест".encode("cp1251").decode("utf8", "surrogateescape"))]
+        [
+            ("Host", "a"),
+            ("X-TEST", "тест".encode("cp1251").decode("utf8", "surrogateescape")),
+        ]
     )
-    assert msg.raw_headers == ((b"x-test", "тест".encode("cp1251")),)
+    assert msg.raw_headers == ((b"Host", b"a"), (b"x-test", "тест".encode("cp1251")))
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -1146,7 +1180,7 @@ def test_http_request_parser_non_utf8(parser: HttpRequestParser) -> None:
 
 
 def test_http_request_parser_two_slashes(parser: HttpRequestParser) -> None:
-    text = b"GET //path HTTP/1.1\r\n\r\n"
+    text = b"GET //path HTTP/1.1\r\nHost: a\r\n\r\n"
     msg = parser.feed_data(text)[0][0][0]
 
     assert msg.method == "GET"
@@ -1167,17 +1201,19 @@ def test_http_request_parser_bad_method(
     parser: HttpRequestParser, rfc9110_5_6_2_token_delim: bytes
 ) -> None:
     with pytest.raises(http_exceptions.BadHttpMethod):
-        parser.feed_data(rfc9110_5_6_2_token_delim + b'ET" /get HTTP/1.1\r\n\r\n')
+        parser.feed_data(
+            rfc9110_5_6_2_token_delim + b'ET" /get HTTP/1.1\r\nHost: a\r\n\r\n'
+        )
 
 
 def test_http_request_parser_bad_version(parser: HttpRequestParser) -> None:
     with pytest.raises(http_exceptions.BadHttpMessage):
-        parser.feed_data(b"GET //get HT/11\r\n\r\n")
+        parser.feed_data(b"GET //get HT/11\r\nHost: a\r\n\r\n")
 
 
 def test_http_request_parser_bad_version_number(parser: HttpRequestParser) -> None:
     with pytest.raises(http_exceptions.BadHttpMessage):
-        parser.feed_data(b"GET /test HTTP/1.32\r\n\r\n")
+        parser.feed_data(b"GET /test HTTP/1.32\r\nHost: a\r\n\r\n")
 
 
 def test_http_request_parser_bad_ascii_uri(parser: HttpRequestParser) -> None:
@@ -1201,15 +1237,15 @@ def test_http_request_max_status_line(parser: HttpRequestParser, size: int) -> N
 def test_http_request_max_status_line_under_limit(parser: HttpRequestParser) -> None:
     path = b"t" * 8172
     messages, upgraded, tail = parser.feed_data(
-        b"GET /path" + path + b" HTTP/1.1\r\n\r\n"
+        b"GET /path" + path + b" HTTP/1.1\r\nHost: a\r\n\r\n"
     )
     msg = messages[0][0]
 
     assert msg.method == "GET"
     assert msg.path == "/path" + path.decode()
     assert msg.version == (1, 1)
-    assert msg.headers == CIMultiDict()
-    assert msg.raw_headers == ()
+    assert msg.headers == CIMultiDict({"Host": "a"})
+    assert msg.raw_headers == ((b"Host", b"a"),)
     assert not msg.should_close
     assert msg.compression is None
     assert not msg.upgrade
@@ -1452,7 +1488,7 @@ def test_http_response_parser_code_not_ascii(
 
 
 def test_http_request_chunked_payload(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntransfer-encoding: chunked\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntransfer-encoding: chunked\r\n\r\n"
     msg, payload = parser.feed_data(text)[0][0]
 
     assert msg.chunked
@@ -1470,12 +1506,13 @@ def test_http_request_chunked_payload(parser: HttpRequestParser) -> None:
 def test_http_request_chunked_payload_and_next_message(
     parser: HttpRequestParser,
 ) -> None:
-    text = b"GET /test HTTP/1.1\r\ntransfer-encoding: chunked\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntransfer-encoding: chunked\r\n\r\n"
     msg, payload = parser.feed_data(text)[0][0]
 
     messages, upgraded, tail = parser.feed_data(
         b"4\r\ndata\r\n4\r\nline\r\n0\r\n\r\n"
         b"POST /test2 HTTP/1.1\r\n"
+        b"Host: a\r\n"
         b"transfer-encoding: chunked\r\n\r\n"
     )
 
@@ -1493,7 +1530,7 @@ def test_http_request_chunked_payload_and_next_message(
 
 
 def test_http_request_chunked_payload_chunks(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntransfer-encoding: chunked\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntransfer-encoding: chunked\r\n\r\n"
     msg, payload = parser.feed_data(text)[0][0]
 
     parser.feed_data(b"4\r\ndata\r")
@@ -1516,7 +1553,7 @@ def test_http_request_chunked_payload_chunks(parser: HttpRequestParser) -> None:
 
 
 def test_parse_chunked_payload_chunk_extension(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\ntransfer-encoding: chunked\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\ntransfer-encoding: chunked\r\n\r\n"
     msg, payload = parser.feed_data(text)[0][0]
 
     parser.feed_data(b"4;test\r\ndata\r\n4\r\nline\r\n0\r\ntest: test\r\n\r\n")
@@ -1528,7 +1565,7 @@ def test_parse_chunked_payload_chunk_extension(parser: HttpRequestParser) -> Non
 
 
 async def test_request_chunked_with_trailer(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nTransfer-Encoding: chunked\r\n\r\n4\r\ntest\r\n0\r\ntest: trailer\r\nsecond: test trailer\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: chunked\r\n\r\n4\r\ntest\r\n0\r\ntest: trailer\r\nsecond: test trailer\r\n\r\n"
     messages, upgraded, tail = parser.feed_data(text)
     assert not tail
     msg, payload = messages[0]
@@ -1538,7 +1575,7 @@ async def test_request_chunked_with_trailer(parser: HttpRequestParser) -> None:
 
 
 async def test_request_chunked_reject_bad_trailer(parser: HttpRequestParser) -> None:
-    text = b"GET /test HTTP/1.1\r\nTransfer-Encoding: chunked\r\n\r\n0\r\nbad\ntrailer\r\n\r\n"
+    text = b"GET /test HTTP/1.1\r\nHost: a\r\nTransfer-Encoding: chunked\r\n\r\n0\r\nbad\ntrailer\r\n\r\n"
     with pytest.raises(http_exceptions.BadHttpMessage, match=r"b'bad\\ntrailer'"):
         parser.feed_data(text)
 
@@ -1549,7 +1586,7 @@ def test_parse_no_length_or_te_on_post(
     request_cls: type[HttpRequestParser],
 ) -> None:
     parser = request_cls(protocol, loop, limit=2**16)
-    text = b"POST /test HTTP/1.1\r\n\r\n"
+    text = b"POST /test HTTP/1.1\r\nHost: a\r\n\r\n"
     msg, payload = parser.feed_data(text)[0][0]
 
     assert payload.is_eof()
@@ -1581,7 +1618,7 @@ def test_parse_length_payload(response: HttpResponseParser) -> None:
 
 
 def test_parse_no_length_payload(parser: HttpRequestParser) -> None:
-    text = b"PUT / HTTP/1.1\r\n\r\n"
+    text = b"PUT / HTTP/1.1\r\nHost: a\r\n\r\n"
     msg, payload = parser.feed_data(text)[0][0]
     assert payload.is_eof()
 
@@ -1753,7 +1790,7 @@ async def test_parse_chunked_payload_with_lf_in_extensions(
 def test_partial_url(parser: HttpRequestParser) -> None:
     messages, upgrade, tail = parser.feed_data(b"GET /te")
     assert len(messages) == 0
-    messages, upgrade, tail = parser.feed_data(b"st HTTP/1.1\r\n\r\n")
+    messages, upgrade, tail = parser.feed_data(b"st HTTP/1.1\r\nHost: a\r\n\r\n")
     assert len(messages) == 1
 
     msg, payload = messages[0]
@@ -1778,7 +1815,7 @@ def test_partial_url(parser: HttpRequestParser) -> None:
 def test_parse_uri_percent_encoded(
     parser: HttpRequestParser, uri: str, path: str, query: dict[str, str], fragment: str
 ) -> None:
-    text = (f"GET {uri} HTTP/1.1\r\n\r\n").encode()
+    text = (f"GET {uri} HTTP/1.1\r\nHost: a\r\n\r\n").encode()
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
 
@@ -1792,7 +1829,7 @@ def test_parse_uri_percent_encoded(
 def test_parse_uri_utf8(parser: HttpRequestParser) -> None:
     if not isinstance(parser, HttpRequestParserPy):
         pytest.xfail("Not valid HTTP. Maybe update py-parser to reject later.")
-    text = ("GET /путь?ключ=знач#фраг HTTP/1.1\r\n\r\n").encode()
+    text = ("GET /путь?ключ=знач#фраг HTTP/1.1\r\nHost: a\r\n\r\n").encode()
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
 
@@ -1804,7 +1841,8 @@ def test_parse_uri_utf8(parser: HttpRequestParser) -> None:
 
 def test_parse_uri_utf8_percent_encoded(parser: HttpRequestParser) -> None:
     text = (
-        "GET %s HTTP/1.1\r\n\r\n" % quote("/путь?ключ=знач#фраг", safe="/?=#")
+        "GET %s HTTP/1.1\r\nHost: a\r\n\r\n"
+        % quote("/путь?ключ=знач#фраг", safe="/?=#")
     ).encode()
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
diff --git a/tests/test_web_urldispatcher.py b/tests/test_web_urldispatcher.py
index 144bd9cd03e..da6a0c38b37 100644
--- a/tests/test_web_urldispatcher.py
+++ b/tests/test_web_urldispatcher.py
@@ -248,7 +248,7 @@ async def test_follow_symlink_directory_traversal(
     # We need to use a raw socket to test this, as the client will normalize
     # the path before sending it to the server.
     reader, writer = await asyncio.open_connection(client.host, client.port)
-    writer.write(b"GET /../private_file HTTP/1.1\r\n\r\n")
+    writer.write(b"GET /../private_file HTTP/1.1\r\nHost: a\r\n\r\n")
     response = await reader.readuntil(b"\r\n\r\n")
     assert b"404 Not Found" in response
     writer.close()
@@ -300,14 +300,14 @@ async def test_follow_symlink_directory_traversal_after_normalization(
     # We need to use a raw socket to test this, as the client will normalize
     # the path before sending it to the server.
     reader, writer = await asyncio.open_connection(client.host, client.port)
-    writer.write(b"GET /my_symlink/../private_file HTTP/1.1\r\n\r\n")
+    writer.write(b"GET /my_symlink/../private_file HTTP/1.1\r\nHost: a\r\n\r\n")
     response = await reader.readuntil(b"\r\n\r\n")
     assert b"404 Not Found" in response
     writer.close()
     await writer.wait_closed()
 
     reader, writer = await asyncio.open_connection(client.host, client.port)
-    writer.write(b"GET /my_symlink/symlink_target_file HTTP/1.1\r\n\r\n")
+    writer.write(b"GET /my_symlink/symlink_target_file HTTP/1.1\r\nHost: a\r\n\r\n")
     response = await reader.readuntil(b"\r\n\r\n")
     assert b"200 OK" in response
     response = await reader.readuntil(b"readable")