python3-django: fix CVE-2026-15337

This patch applies the upstream fix as referenced in [2], using the commit shown in [1]. [1] https://github.com/django/django/commit/c72a5dbb64d0777f3f471f1be94e8b2ca91e0959 [2] https://nvd.nist.gov/vuln/detail/CVE-2026-15337 Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com> Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>
2026-09-09 06:40:17 +00:00 · 2026-09-01 10:17:59 +05:30
parent 3bc6095e25
commit e1fadab9dd
2 changed files with 164 additions and 0 deletions
@@ -0,0 +1,163 @@
+From 8c63ca97dd33e3cb7e4a6f78c5f616f2e45ecaf1 Mon Sep 17 00:00:00 2001
+From: Natalia <124304+nessita@users.noreply.github.com>
+Date: Fri, 10 Jul 2026 18:30:21 -0300
+Subject: [PATCH] [5.2.x] Fixed CVE-2026-15337 -- Mitigated potential DoS in
+ check_for_language().
+
+Language codes longer than 500 characters are now rejected before the
+cached lookup, so they are no longer retained as cache keys consuming
+memory from each process.
+
+Thanks Jaeyoung Jang for the report, and Sarah Boyce for reviews.
+
+Backport of 27137e655e442e81095f1f8f77ff3870d9fdf169 from main.
+
+CVE: CVE-2026-15337
+Upstream-Status: Backport [https://github.com/django/django/commit/c72a5dbb64d0777f3f471f1be94e8b2ca91e0959]
+
+Backport Changes:
+- Dropped the docs/release file as current version
+  is 5.0.14 for Scarthgap.
+
+(cherry picked from commit c72a5dbb64d0777f3f471f1be94e8b2ca91e0959)
+Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
+---
+ django/test/signals.py                 |  2 +-
+ django/utils/translation/trans_real.py | 27 ++++++++++++++++++--------
+ docs/ref/utils.txt                     |  3 +++
+ tests/i18n/tests.py                    | 24 ++++++++++++++++++++++-
+ 4 files changed, 46 insertions(+), 10 deletions(-)
+
+diff --git a/django/test/signals.py b/django/test/signals.py
+index c16f4aa5ee..51ff9c3d98 100644
+--- a/django/test/signals.py
+++ b/django/test/signals.py
+@@ -152,7 +152,7 @@ def language_changed(*, setting, **kwargs):
+         from django.utils.translation import trans_real
+ 
+         trans_real._translations = {}
+-        trans_real.check_for_language.cache_clear()
+        trans_real.translation_catalog_exists.cache_clear()
+ 
+ 
+ @receiver(setting_changed)
+diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
+index 1c42330451..67937a6470 100644
+--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
+@@ -31,9 +31,10 @@ _default = None
+ # magic gettext number to separate context from message
+ CONTEXT_SEPARATOR = "\x04"
+ 
+-# Maximum number of characters that will be parsed from the Accept-Language
+-# header or cookie to prevent possible denial of service or memory exhaustion
+-# attacks. About 10x longer than the longest value shown on MDN’s
+# Maximum length of a language code that will be processed, to prevent possible
+# denial of service or memory exhaustion attacks. Language codes are taken from
+# the Accept-Language header, the language cookie, the URL path prefix, or the
+# set_language() view. 500 is about 10x the longest value shown on MDN's
+ # Accept-Language page.
+ LANGUAGE_CODE_MAX_LENGTH = 500
+ 
+@@ -65,7 +66,7 @@ def reset_cache(*, setting, **kwargs):
+     languages should no longer be accepted.
+     """
+     if setting in ("LANGUAGES", "LANGUAGE_CODE"):
+-        check_for_language.cache_clear()
+        translation_catalog_exists.cache_clear()
+         get_languages.cache_clear()
+         get_supported_language_variant.cache_clear()
+ 
+@@ -461,19 +462,29 @@ def all_locale_paths():
+     return [globalpath, *settings.LOCALE_PATHS, *app_paths]
+ 
+ 
+-@functools.lru_cache(maxsize=1000)
+ def check_for_language(lang_code):
+     """
+     Check whether there is a global language file for the given language
+     code. This is used to decide whether a user-provided language is
+     available.
+ 
+-    lru_cache should have a maxsize to prevent from memory exhaustion attacks,
+-    as the provided language codes are taken from the HTTP request. See also
+    Reject over-length codes before the cached lookup so that oversized,
+    attacker-controlled values are not retained as cache keys.
+    """
+    if lang_code is None or len(lang_code) > LANGUAGE_CODE_MAX_LENGTH:
+        return False
+    return translation_catalog_exists(lang_code)
+
+
+@functools.lru_cache(maxsize=1000)
+def translation_catalog_exists(lang_code):
+    """Return whether a translation catalog exists for the given language code.
+
+    lru_cache should have a maxsize to prevent memory exhaustion attacks. See:
+     <https://www.djangoproject.com/weblog/2007/oct/26/security-fix/>.
+     """
+     # First, a quick check to make sure lang_code is well-formed (#21458)
+-    if lang_code is None or not language_code_re.search(lang_code):
+    if not language_code_re.search(lang_code):
+         return False
+     return any(
+         gettext_module.find("django", path, [to_locale(lang_code)]) is not None
+diff --git a/docs/ref/utils.txt b/docs/ref/utils.txt
+index 1d0178a263..1f44b4eb85 100644
+--- a/docs/ref/utils.txt
+++ b/docs/ref/utils.txt
+@@ -1082,6 +1082,9 @@ For a complete discussion on the usage of the following see the
+     code (e.g. 'fr', 'pt_BR'). This is used to decide whether a user-provided
+     language is available.
+ 
+    ``lang_code`` has a maximum accepted length of 500 characters. ``False``
+    is returned if it exceeds this limit, before any language-file lookup.
+
+ .. function:: get_language()
+ 
+     Returns the currently selected language code. Returns ``None`` if
+diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
+index f74e33bf79..b83c9d6a68 100644
+--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
+@@ -58,7 +58,10 @@ from django.utils.translation.reloader import (
+     translation_file_changed,
+     watch_for_translation_changes,
+ )
+-from django.utils.translation.trans_real import LANGUAGE_CODE_MAX_LENGTH
+from django.utils.translation.trans_real import (
+    LANGUAGE_CODE_MAX_LENGTH,
+    translation_catalog_exists,
+)
+ 
+ from .forms import CompanyForm, I18nForm, SelectDateForm
+ from .models import Company, TestModel
+@@ -1995,6 +1998,25 @@ class CountrySpecificLanguageTests(SimpleTestCase):
+         self.assertFalse(check_for_language("tr-TR.UTF8"))
+         self.assertFalse(check_for_language("de-DE.utf-8"))
+ 
+    def test_check_for_language_lang_code_max_length(self):
+        self.addCleanup(translation_catalog_exists.cache_clear)
+
+        # Overly long codes are rejected before the cached lookup, so they are
+        # not retained as cache keys, potentially consuming too much memory.
+        # Codes at the maximum length can reach the cached lookup.
+        for length, cache_size in [
+            (LANGUAGE_CODE_MAX_LENGTH - 1, 1),
+            (LANGUAGE_CODE_MAX_LENGTH, 1),
+            (LANGUAGE_CODE_MAX_LENGTH + 1, 0),
+        ]:
+            translation_catalog_exists.cache_clear()
+            with self.subTest(length=length):
+                self.assertIs(check_for_language("a" * length), False)
+                self.assertEqual(
+                    translation_catalog_exists.cache_info().currsize,
+                    cache_size,
+                )
+
+     def test_check_for_language_null(self):
+         self.assertIs(trans_null.check_for_language("en"), True)
+ 
+-- 
+2.44.4
+