File CVE-2026-0865-wsgiref-ctrl-chars.patch of Package python311
From 2c84d7875f35d3d1d0fbc170271227cc95752fa5 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] [3.11] 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 | 18 +++++
Lib/wsgiref/headers.py | 34 ++++++----
Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst | 2
4 files changed, 47 insertions(+), 14 deletions(-)
create mode 100644 Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst
Index: Python-3.11.14/Lib/test/support/__init__.py
===================================================================
--- Python-3.11.14.orig/Lib/test/support/__init__.py 2026-02-11 23:22:45.373477280 +0100
+++ Python-3.11.14/Lib/test/support/__init__.py 2026-02-11 23:23:25.641652256 +0100
@@ -2294,3 +2294,10 @@
fails_with_expat_2_6_0 = (unittest.expectedFailure
if is_expat_2_6_0
else lambda test: test)
+
+
+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"]
Index: Python-3.11.14/Lib/test/test_wsgiref.py
===================================================================
--- Python-3.11.14.orig/Lib/test/test_wsgiref.py 2026-02-11 23:22:38.512011986 +0100
+++ Python-3.11.14/Lib/test/test_wsgiref.py 2026-02-11 23:24:19.545119499 +0100
@@ -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.test_httpservers import NoLogRequestHandler
from unittest import TestCase
from wsgiref.util import setup_testing_defaults
@@ -503,6 +503,22 @@
'\r\n'
)
+ def testRaisesControlCharacters(self):
+ for c0 in control_characters_c0():
+ with self.subTest(c0):
+ headers = Headers()
+ self.assertRaises(ValueError, headers.__setitem__, f"key{c0}", "val")
+ self.assertRaises(ValueError, headers.add_header, f"key{c0}", "val", param="param")
+ # HTAB (\x09) is allowed in values, not names.
+ if c0 == "\t":
+ headers["key"] = f"val{c0}"
+ headers.add_header("key", f"val{c0}")
+ headers.setdefault(f"key", f"val{c0}")
+ else:
+ self.assertRaises(ValueError, headers.__setitem__, "key", f"val{c0}")
+ 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-3.11.14/Lib/wsgiref/headers.py
===================================================================
--- Python-3.11.14.orig/Lib/wsgiref/headers.py 2026-02-11 23:22:38.927685306 +0100
+++ Python-3.11.14/Lib/wsgiref/headers.py 2026-02-11 23:24:19.545709612 +0100
@@ -9,6 +9,11 @@
# existence of which force quoting of the parameter value.
import re
tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]')
+# Disallowed characters for headers and values.
+# HTAB (\x09) is allowed in header values, but
+# not in header names. (RFC 9110 Section 5.5)
+_name_disallowed_re = re.compile(r'[\x00-\x1F\x7F]')
+_value_disallowed_re = re.compile(r'[\x00-\x08\x0A-\x1F\x7F]')
def _formatparam(param, value=None, quote=1):
"""Convenience function to format and return a key=value pair.
@@ -35,12 +40,15 @@
self._headers = headers
if __debug__:
for k, v in headers:
- self._convert_string_type(k)
- self._convert_string_type(v)
+ self._convert_string_type(k, name=True)
+ self._convert_string_type(v, name=False)
- def _convert_string_type(self, value):
+ def _convert_string_type(self, value, *, name):
"""Convert/check value type."""
if type(value) is str:
+ regex = (_name_disallowed_re if name else _value_disallowed_re)
+ if regex.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)))
@@ -53,14 +61,14 @@
"""Set the value of a header."""
del self[name]
self._headers.append(
- (self._convert_string_type(name), self._convert_string_type(val)))
+ (self._convert_string_type(name, name=True), self._convert_string_type(val, name=False)))
def __delitem__(self,name):
"""Delete all occurrences of a header, if present.
Does *not* raise an exception if the header is missing.
"""
- name = self._convert_string_type(name.lower())
+ name = self._convert_string_type(name.lower(), name=True)
self._headers[:] = [kv for kv in self._headers if kv[0].lower() != name]
def __getitem__(self,name):
@@ -87,13 +95,13 @@
fields deleted and re-inserted are always appended to the header list.
If no fields exist with the given name, returns an empty list.
"""
- name = self._convert_string_type(name.lower())
+ name = self._convert_string_type(name.lower(), name=True)
return [kv[1] for kv in self._headers if kv[0].lower()==name]
def get(self,name,default=None):
"""Get the first header value for 'name', or return 'default'"""
- name = self._convert_string_type(name.lower())
+ name = self._convert_string_type(name.lower(), name=True)
for k,v in self._headers:
if k.lower()==name:
return v
@@ -148,8 +156,8 @@
and value 'value'."""
result = self.get(name)
if result is None:
- self._headers.append((self._convert_string_type(name),
- self._convert_string_type(value)))
+ self._headers.append((self._convert_string_type(name, name=True),
+ self._convert_string_type(value, name=False)))
return value
else:
return result
@@ -172,13 +180,13 @@
"""
parts = []
if _value is not None:
- _value = self._convert_string_type(_value)
+ _value = self._convert_string_type(_value, name=False)
parts.append(_value)
for k, v in _params.items():
- k = self._convert_string_type(k)
+ k = self._convert_string_type(k, name=True)
if v is None:
parts.append(k.replace('_', '-'))
else:
- v = self._convert_string_type(v)
+ v = self._convert_string_type(v, name=False)
parts.append(_formatparam(k.replace('_', '-'), v))
- self._headers.append((self._convert_string_type(_name), "; ".join(parts)))
+ self._headers.append((self._convert_string_type(_name, name=True), "; ".join(parts)))
Index: Python-3.11.14/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-3.11.14/Misc/NEWS.d/next/Security/2026-01-16-11-07-36.gh-issue-143916.dpWeOD.rst 2026-02-11 23:22:49.891193395 +0100
@@ -0,0 +1,2 @@
+Reject C0 control characters within wsgiref.headers.Headers fields, values,
+and parameters.
