From ccdade1a0262537868d7ca64374de3d957ca50c5 Mon Sep 17 00:00:00 2001
From: Natalia <124304+nessita@users.noreply.github.com>
Date: Tue, 19 Sep 2023 09:51:48 -0300
Subject: [3.2.x] Fixed CVE-2023-43665 -- Mitigated potential DoS in
 django.utils.text.Truncator when truncating HTML text.

Thanks Wenchao Li of Alibaba Group for the report.
---
 docs/ref/templates/builtins.txt | 20 ++++++++++++++++++++
 docs/releases/3.2.22.txt        | 18 +++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

(limited to 'docs')

diff --git a/docs/ref/templates/builtins.txt b/docs/ref/templates/builtins.txt
index 22509a2a7e..a6fd97175b 100644
--- a/docs/ref/templates/builtins.txt
+++ b/docs/ref/templates/builtins.txt
@@ -2348,6 +2348,16 @@ If ``value`` is ``"<p>Joel is a slug</p>"``, the output will be
 
 Newlines in the HTML content will be preserved.
 
+.. admonition:: Size of input string
+
+    Processing large, potentially malformed HTML strings can be
+    resource-intensive and impact service performance. ``truncatechars_html``
+    limits input to the first five million characters.
+
+.. versionchanged:: 3.2.22
+
+    In older versions, strings over five million characters were processed.
+
 .. templatefilter:: truncatewords
 
 ``truncatewords``
@@ -2386,6 +2396,16 @@ If ``value`` is ``"<p>Joel is a slug</p>"``, the output will be
 
 Newlines in the HTML content will be preserved.
 
+.. admonition:: Size of input string
+
+    Processing large, potentially malformed HTML strings can be
+    resource-intensive and impact service performance. ``truncatewords_html``
+    limits input to the first five million characters.
+
+.. versionchanged:: 3.2.22
+
+    In older versions, strings over five million characters were processed.
+
 .. templatefilter:: unordered_list
 
 ``unordered_list``
diff --git a/docs/releases/3.2.22.txt b/docs/releases/3.2.22.txt
index 6e1815de11..cfedc41de8 100644
--- a/docs/releases/3.2.22.txt
+++ b/docs/releases/3.2.22.txt
@@ -6,4 +6,20 @@ Django 3.2.22 release notes
 
 Django 3.2.22 fixes a security issue with severity "moderate" in 3.2.21.
 
-...
+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.
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