File CVE-2026-0865-wsgiref-ctrl-chars.patch of Package python3.42753
From 123bfbbe9074ef7fa28e1e7b25575665296560fa Mon Sep 17 00:00:00 2001
From: "Gregory P. Smith" <68491+gpshead@users.noreply.github.com>
Date: Sat, 17 Jan 2026 10:23:57 -0800
Subject: [PATCH] [3.10] gh-143916: Reject control characters in
wsgiref.headers.Headers (GH-143917) (GH-143973)
gh-143916: Reject control characters in wsgiref.headers.Headers (GH-143917)
* Add 'test.support' fixture for C0 control characters
* gh-143916: Reject control characters in wsgiref.headers.Headers
(cherry picked from commit f7fceed79ca1bceae8dbe5ba5bc8928564da7211)
(cherry picked from commit 22e4d55285cee52bc4dbe061324e5f30bd4dee58)
Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>
Co-authored-by: Seth Michael Larson <seth@python.org>
---
Lib/test/support/__init__.py | 9 +++++++-
Lib/test/test_wsgiref.py | 11 ++++++++++
Lib/wsgiref/headers.py | 3 ++
Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst | 2 +
4 files changed, 24 insertions(+), 1 deletion(-)
create mode 100644 Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst
Index: Python-3.6.15/Lib/test/support/__init__.py
===================================================================
--- Python-3.6.15.orig/Lib/test/support/__init__.py 2026-02-12 16:49:06.070309762 +0100
+++ Python-3.6.15/Lib/test/support/__init__.py 2026-02-12 16:50:30.059556463 +0100
@@ -113,7 +113,7 @@
"run_with_locale", "swap_item",
"swap_attr", "Matcher", "set_memlimit", "SuppressCrashReport", "sortdict",
"run_with_tz", "PGO", "missing_compiler_executable", "fd_count",
- "fails_with_expat_2_6_0", "is_expat_2_6_0"
+ "fails_with_expat_2_6_0", "is_expat_2_6_0", "control_characters_c0",
]
class Error(Exception):
@@ -2894,3 +2894,10 @@
fails_with_expat_2_6_0 = (unittest.expectedFailure
if is_expat_2_6_0
else lambda test: test)
+
+
+def control_characters_c0():
+ """Returns a list of C0 control characters as strings.
+ C0 control characters defined as the byte range 0x00-0x1F, and 0x7F.
+ """
+ return [chr(c) for c in range(0x00, 0x20)] + ["\x7F"]
Index: Python-3.6.15/Lib/test/test_wsgiref.py
===================================================================
--- Python-3.6.15.orig/Lib/test/test_wsgiref.py 2026-02-12 16:49:03.724716993 +0100
+++ Python-3.6.15/Lib/test/test_wsgiref.py 2026-02-12 16:49:06.435093966 +0100
@@ -1,6 +1,7 @@
from unittest import mock
from test import support
from test.test_httpservers import NoLogRequestHandler
+from test.support import control_characters_c0
from unittest import TestCase
from wsgiref.util import setup_testing_defaults
from wsgiref.headers import Headers
@@ -517,6 +518,16 @@
'\r\n'
)
+ def testRaisesControlCharacters(self):
+ headers = Headers()
+ for c0 in control_characters_c0():
+ self.assertRaises(ValueError, headers.__setitem__, f"key{c0}", "val")
+ self.assertRaises(ValueError, headers.__setitem__, "key", f"val{c0}")
+ self.assertRaises(ValueError, headers.add_header, f"key{c0}", "val", param="param")
+ self.assertRaises(ValueError, headers.add_header, "key", f"val{c0}", param="param")
+ self.assertRaises(ValueError, headers.add_header, "key", "val", param=f"param{c0}")
+
+
class ErrorHandler(BaseCGIHandler):
"""Simple handler subclass for testing BaseHandler"""
Index: Python-3.6.15/Lib/wsgiref/headers.py
===================================================================
--- Python-3.6.15.orig/Lib/wsgiref/headers.py 2026-02-12 16:49:01.439670146 +0100
+++ Python-3.6.15/Lib/wsgiref/headers.py 2026-02-12 16:49:06.435310874 +0100
@@ -9,6 +9,7 @@
# existence of which force quoting of the parameter value.
import re
tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]')
+_control_chars_re = re.compile(r'[\x00-\x1F\x7F]')
def _formatparam(param, value=None, quote=1):
"""Convenience function to format and return a key=value pair.
@@ -41,6 +42,8 @@
def _convert_string_type(self, value):
"""Convert/check value type."""
if type(value) is str:
+ if _control_chars_re.search(value):
+ raise ValueError("Control characters not allowed in headers")
return value
raise AssertionError("Header names/values must be"
" of type str (got {0})".format(repr(value)))
Index: Python-3.6.15/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ Python-3.6.15/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst 2026-02-12 16:49:06.435451990 +0100
@@ -0,0 +1,2 @@
+Reject C0 control characters within wsgiref.headers.Headers fields, values,
+and parameters.
