Description
An issue was discovered in 5.1 before 5.1.14, 4.2 before 4.2.26, and 5.2 before 5.2.8. NFKC normalization in Python is slow on Windows. As a consequence, `django.http.HttpResponseRedirect`, `django.http.HttpResponsePermanentRedirect`, and the shortcut `django.shortcuts.redirect` were subject to a potential denial-of-service attack via certain inputs with a very large number of Unicode characters. Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected. Django would like to thank Seokchan Yoon for reporting this issue.
Problem types
CWE-407: Inefficient Algorithmic Complexity
Product status
5.2 (semver) before 5.2.8
5.2.8 (semver)
5.1 (semver) before 5.1.14
5.1.14 (semver)
4.2 (semver) before 4.2.26
4.2.26 (semver)
Timeline
| 2025-10-02: | Initial report received. |
| 2025-10-09: | Vulnerability confirmed. |
| 2025-11-05: | Security release issued. |
Credits
Seokchan Yoon
Jacob Walls
Natalia Bidart
References
docs.djangoproject.com/en/dev/releases/security/ (Django security archive)
groups.google.com/g/django-announce (Django releases announcements)
www.djangoproject.com/weblog/2025/nov/05/security-releases/ (Django security releases issued: 5.2.8, 5.1.14, and 4.2.26)
