What’s Vulnerable › Vulnerabilities

CVE-2025-64458: Potential denial-of-service vulnerability in HttpResponseRedirect and HttpResponsePermanentRedirect on Windows

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-11-05 · updated 2026-06-17
• Weakness: CWE-407

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.

Affected products

• Django: from 4.2 before 4.2.26; from 5.1 before 5.1.14; from 5.2 before 5.2.8 — fixed in 4.2.26, 5.1.14, 5.2.8
• Pypi Django: from 5.2a1 before 5.2.8; from 5.0a1 before 5.1.14; before 4.2.26; 5.2, 5.2.1, 5.2.2, 5.2.3, 5.2.4, 5.2.5 (+402) — fixed in 5.2.8, 5.1.14, 4.2.26

How to fix

Upgrade to a fixed version: Django 4.2.26, 5.1.14, 5.2.8; Pypi Django 5.2.8, 5.1.14, 4.2.26. Check the vendor advisory for mitigations.

References

• https://docs.djangoproject.com/en/dev/releases/security/
• https://groups.google.com/g/django-announce
• https://www.djangoproject.com/weblog/2025/nov/05/security-releases/

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