meta-openembedded/meta-python/recipes-devtools/python/python3-aiohttp/CVE-2026-34520.patch

From 661f91935d061a3d7d554f2c808c8a14f3122991 Mon Sep 17 00:00:00 2001
From: Rodrigo Nogueira <rodrigo.b.nogueira@gmail.com>
Date: Wed, 11 Mar 2026 20:38:17 -0300
Subject: [PATCH] [PR #12231/7043bc56 backport][3.13] Adjust header value
 character checks to RFC 9110 (#12235)

CVE: CVE-2026-34520
Upstream-Status: Backport [https://github.com/aio-libs/aiohttp/commit/9370b9714a7a56003cacd31a9b4ae16eab109ba4]

Backport Changes:
- Included the C-parser null-byte validation from upstream prerequisite
  commit db560cfeab32aa35f3d06f7a24238bedc01ffe2b because the Scarthgap
  3.9.5 recipe patch stack does not contain that prerequisite.
- Used the target's local `raw_value` bytes object when raising
  `InvalidHeader`, since aiohttp 3.9.5 converts
  `_raw_value` before checking.
- Added a response-parser regression test for the C-parser validation.
- Omitted the generated aiohttp/_http_parser.c changes because the
  Scarthgap recipe regenerates this file from _http_parser.pyx with
  Cython.

Co-authored-by: rodrigo.nogueira <rodrigo.nogueira@prf.gov.br>
(cherry picked from commit 9370b9714a7a56003cacd31a9b4ae16eab109ba4)
Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
---
 CHANGES/12231.bugfix.rst  |  2 ++
 aiohttp/_http_parser.pyx  |  7 +++++++
 aiohttp/http_parser.py    |  9 ++++++++-
 tests/test_http_parser.py | 17 +++++++++++++++++
 4 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 CHANGES/12231.bugfix.rst

diff --git a/CHANGES/12231.bugfix.rst b/CHANGES/12231.bugfix.rst
new file mode 100644
index 000000000..cd74bd1e7
--- /dev/null
+++ b/CHANGES/12231.bugfix.rst
@@ -0,0 +1,2 @@
+Adjusted pure-Python request header value validation to align with RFC 9110 control-character handling, while preserving lax response parser behavior, and added regression tests for Host/header control-character cases.
+-- by :user:`rodrigobnogueira`.
diff --git a/aiohttp/_http_parser.pyx b/aiohttp/_http_parser.pyx
index cc8b13cfb..496498d6f 100644
--- a/aiohttp/_http_parser.pyx
+++ b/aiohttp/_http_parser.pyx
@@ -387,5 +387,12 @@ cdef class HttpParser:
             value = raw_value.decode('utf-8', 'surrogateescape')
 
+            # reject null bytes in header values - matches the Python parser
+            # check at http_parser.py. llhttp in lenient mode doesn't reject
+            # these itself, so we need to catch them here.
+            # ref: RFC 9110 section 5.5 (CTL chars forbidden in field values)
+            if "\x00" in value:
+                raise InvalidHeader(raw_value)
+
             self._headers.add(name, value)
             if len(self._headers) > self._max_headers:
                 raise BadHttpMessage("Too many headers received")
diff --git a/aiohttp/http_parser.py b/aiohttp/http_parser.py
index 95ac28252..a7fec7f01 100644
--- a/aiohttp/http_parser.py
+++ b/aiohttp/http_parser.py
@@ -73,6 +73,10 @@ ASCIISET: Final[Set[str]] = set(string.printable)
 #     token = 1*tchar
 _TCHAR_SPECIALS: Final[str] = re.escape("!#$%&'*+-.^_`|~")
 TOKENRE: Final[Pattern[str]] = re.compile(f"[0-9A-Za-z{_TCHAR_SPECIALS}]+")
+# https://www.rfc-editor.org/rfc/rfc9110#section-5.5-5
+_FIELD_VALUE_FORBIDDEN_CTL_RE: Final[Pattern[str]] = re.compile(
+    r"[\x00-\x08\x0a-\x1f\x7f]"
+)
 VERSRE: Final[Pattern[str]] = re.compile(r"HTTP/(\d)\.(\d)", re.ASCII)
 DIGITS: Final[Pattern[str]] = re.compile(r"\d+", re.ASCII)
 HEXDIGITS: Final[Pattern[bytes]] = re.compile(rb"[0-9a-fA-F]+")
@@ -200,7 +204,10 @@ class HeadersParser:
             value = bvalue.decode("utf-8", "surrogateescape")
 
             # https://www.rfc-editor.org/rfc/rfc9110.html#section-5.5-5
-            if "\n" in value or "\r" in value or "\x00" in value:
+            if self._lax:
+                if "\n" in value or "\r" in value or "\x00" in value:
+                    raise InvalidHeader(bvalue)
+            elif _FIELD_VALUE_FORBIDDEN_CTL_RE.search(value):
                 raise InvalidHeader(bvalue)
 
             headers.add(name, value)
diff --git a/tests/test_http_parser.py b/tests/test_http_parser.py
index cb562f598..be7446e0a 100644
--- a/tests/test_http_parser.py
+++ b/tests/test_http_parser.py
@@ -210,6 +210,9 @@ def test_bad_header_name(parser: Any, rfc9110_5_6_2_token_delim: str) -> None:
         "Foo : bar",  # https://www.rfc-editor.org/rfc/rfc9112.html#section-5.1-2
         "Foo\t: bar",
         "\xffoo: bar",
+        "Foo: abc\x01def",  # CTL bytes forbidden per RFC 9110 §5.5
+        "Foo: abc\x7fdef",  # DEL is also a CTL byte
+        "Foo: abc\x1fdef",
     ),
 )
 def test_bad_headers(parser: Any, hdr: str) -> None:
@@ -218,6 +221,20 @@ def test_bad_headers(parser: Any, hdr: str) -> None:
         parser.feed_data(text)
 
 
+def test_ctl_host_header_bad_characters(parser: HttpRequestParser) -> None:
+    """CTL byte in Host header must be rejected."""
+    text = b"GET /test HTTP/1.1\r\nHost: trusted.example\x01@bad.test\r\n\r\n"
+    with pytest.raises(http_exceptions.BadHttpMessage):
+        parser.feed_data(text)
+
+
+def test_null_byte_in_response_header_value(
+    response: HttpResponseParser,
+) -> None:
+    with pytest.raises(http_exceptions.InvalidHeader):
+        response.feed_data(b"HTTP/1.1 200 OK\r\nFoo: abc\x00def\r\n\r\n")
+
+
 def test_unpaired_surrogate_in_header_py(loop: Any, protocol: Any) -> None:
     parser = HttpRequestParserPy(
         protocol,
-- 
2.35.6