File CVE-2026-0865-wsgiref-ctrl-chars.patch of Package python310
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 | 7 +++++++
Lib/test/test_wsgiref.py | 12 +++++++++++-
Lib/wsgiref/headers.py | 3 +++
.../2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst | 2 ++
4 files changed, 23 insertions(+), 1 deletion(-)
create mode 100644 Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 0d3b9634f10248..d0492fe1914343 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2157,3 +2157,10 @@ def adjust_int_max_str_digits(max_digits):
yield
finally:
sys.set_int_max_str_digits(current)
+
+
+def control_characters_c0() -> list[str]:
+ """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"]
diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py
index 42094f467731d4..01ca51ba458587 100644
--- a/Lib/test/test_wsgiref.py
+++ b/Lib/test/test_wsgiref.py
@@ -1,6 +1,6 @@
from unittest import mock
from test import support
-from test.support import socket_helper
+from test.support import socket_helper, control_characters_c0
from test.support import warnings_helper
from test.test_httpservers import NoLogRequestHandler
from unittest import TestCase
@@ -527,6 +527,16 @@ def testExtras(self):
'\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"""
diff --git a/Lib/wsgiref/headers.py b/Lib/wsgiref/headers.py
index fab851c5a44430..fd98e85d75492b 100644
--- a/Lib/wsgiref/headers.py
+++ b/Lib/wsgiref/headers.py
@@ -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 __init__(self, headers=None):
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)))
diff --git a/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst b/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst
new file mode 100644
index 00000000000000..44bd0b27059f94
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst
@@ -0,0 +1,2 @@
+Reject C0 control characters within wsgiref.headers.Headers fields, values,
+and parameters.
