PyPi: Django

CVE-2023-43665

Safety vulnerability ID: 61586

This vulnerability was reviewed by experts

The information on this page was manually curated by our Cybersecurity Intelligence Team.

Created at Nov 03, 2023 Updated at Nov 05, 2024
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Advisory

Affected versions of Django are vulnerable to Denial-of-Service via django.utils.text.Truncator. The django.utils.text.Truncator chars() and words() methods (when used with html=True) are subject to a potential DoS (denial of service) attack via certain inputs with very long, potentially malformed HTML text. The chars() and words() methods are used to implement the truncatechars_html and truncatewords_html template filters, which are thus also vulnerable. NOTE: this issue exists because of an incomplete fix for CVE-2019-14232.

Affected package

django

Latest version: 5.1.3

A high-level Python web framework that encourages rapid development and clean, pragmatic design.

Affected versions

Fixed versions

Vulnerability changelog

==========================

*October 4, 2023*

Django 4.2.6 fixes a security issue with severity "moderate" and several bugs
in 4.2.5.

CVE-2023-43665: Denial-of-service possibility in ``django.utils.text.Truncator``
================================================================================

Following the fix for :cve:`2019-14232`, the regular expressions used in the
implementation of ``django.utils.text.Truncator``'s ``chars()`` and ``words()``
methods (with ``html=True``) were revised and improved. However, these regular
expressions still exhibited linear backtracking complexity, so when given a
very long, potentially malformed HTML input, the evaluation would still be
slow, leading to a potential denial of service vulnerability.

The ``chars()`` and ``words()`` methods are used to implement the
:tfilter:`truncatechars_html` and :tfilter:`truncatewords_html` template
filters, which were thus also vulnerable.

The input processed by ``Truncator``, when operating in HTML mode, has been
limited to the first five million characters in order to avoid potential
performance and memory issues.

Bugfixes
========

* Fixed a regression in Django 4.2.5 where overriding the deprecated
``DEFAULT_FILE_STORAGE`` and ``STATICFILES_STORAGE`` settings in tests caused
the main ``STORAGES`` to mutate (:ticket:`34821`).

* Fixed a regression in Django 4.2 that caused unnecessary casting of string
based fields (``CharField``, ``EmailField``, ``TextField``, ``CICharField``,
``CIEmailField``, and ``CITextField``) used with the ``__isnull`` lookup on
PostgreSQL. As a consequence, the pre-Django 4.2 indexes didn't match and
were not used by the query planner (:ticket:`34840`).

You may need to recreate indexes propagated to the database with Django
4.2 - 4.2.5 as they contain unnecessary ``::text`` casting that is avoided as
of this release.


==========================

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Severity Details

CVSS Base Score

HIGH 7.5

CVSS v3 Details

HIGH 7.5
Attack Vector (AV)
NETWORK
Attack Complexity (AC)
LOW
Privileges Required (PR)
NONE
User Interaction (UI)
NONE
Scope (S)
UNCHANGED
Confidentiality Impact (C)
NONE
Integrity Impact (I)
NONE
Availability Availability (A)
HIGH