CVE-2026-1285: Django Denial-of-Service Vulnerability Due to Inefficient Algorithmic Complexity
Summary
CVE-2026-1285: Django has Inefficient Algorithmic Complexity. Affects django across 3 version ranges.
>= 4.2a1, < 4.2.28
>= 5.2a1, < 5.2.11
>= 6.0a1, < 6.0.2
Fixed in 4.2.28, 5.2.11 or 6.0.2, depending on the release line you run. How to fix ↓
Also tracked for
- django · Bitnami
The same CVE-2026-1285 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design. It is widely used for building web applications and provides a robust set of features, including an ORM, authentication, and an admin interface. However, certain versions of Django are vulnerable to an issue that can lead to denial-of-service attacks when handling specific HTML inputs.
Vulnerability Detail
An issue was discovered in Django versions 6.0 before 6.0.2, 5.2 before 5.2.11, and 4.2 before 4.2.28. The vulnerability lies in the django.utils.text.Truncator.chars() and Truncator.words() methods when the html parameter is set to True. Attackers can exploit this by sending crafted inputs containing a large number of unmatched HTML end tags, potentially leading to a denial-of-service condition. Unsupported versions such as 5.0.x, 4.1.x, and 3.2.x may also be affected, although they have not been evaluated.
How To Fix
Latest published version: 6.1.2 as of 22 Oct 2026
pip install --upgrade "django==6.1.2"Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
>= 4.2a1, < 4.2.284.2.28pip install --upgrade "django==4.2.28" -
>= 5.2a1, < 5.2.115.2.11pip install --upgrade "django==5.2.11" -
>= 6.0a1, < 6.0.26.0.2pip install --upgrade "django==6.0.2"
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Workaround
As a temporary workaround, avoid using the html=True parameter in the Truncator.chars() and Truncator.words() methods, as well as the truncatechars_html and truncatewords_html template filters until the package is updated.
Conclusion
In summary, Django has a vulnerability that can lead to denial-of-service attacks due to inefficient algorithmic complexity in certain methods when handling HTML inputs. It is crucial to update to the patched versions to mitigate this risk.
See every vulnerability recorded for django →
FAQ
Django versions 6.0 before 6.0.2, 5.2 before 5.2.11, and 4.2 before 4.2.28 are affected. Unsupported versions like 5.0.x, 4.1.x, and 3.2.x may also be vulnerable.
The vulnerability can lead to denial-of-service attacks, causing the application to become unresponsive when processing crafted HTML inputs.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Yes, you can mitigate the risk by avoiding the use of the html=True parameter in the affected methods and filters until you can apply the update.
The CVSS score of this vulnerability is 2.7, indicating a low severity level.
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