CVE-2025-64458: Django denial of service in HttpResponseRedirect on Windows

CVE-2025-64458 · Severity: high · CVSS 7.5 · Published 2025-11-05

Django, a popular web framework, is vulnerable to a denial-of-service attack when running on Windows. An attacker can send specially crafted web requests containing a large number of specific Unicode characters to overwhelm the server's processor. This can cause the website to become slow or completely unresponsive, disrupting business operations and service availability.

Technologies: Django (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2025-64458 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-64458 being exploited in the wild.
How severe is CVE-2025-64458?
High severity, with a CVSS score of 7.5, published 5 November 2025.
Which products and versions are affected?
Django (PyPI) ECOSYSTEM:introduced=4.2,fixed=4.2.26,introduced=5.1,fixed=5.1.14,introduced=5.2,fixed=5.2.8, ECOSYSTEM:introduced=5.2a1,fixed=5.2.8.
Is there a fix for CVE-2025-64458?
Yes. Django (PyPI): upgrade to 5.2.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-64458 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2025-64458?
Check whether you run Django (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Django (PyPI): upgrade to 5.2.8 or later
    pip install "Django>=5.2.8"

Technical details

A denial-of-service (DoS) vulnerability exists in Django when deployed on Windows systems. The root cause is the slow performance of NFKC (Normalization Form Compatibility Composition) normalization in Python on Windows. An attacker can exploit this by providing inputs containing a very large number of Unicode characters to `django.http.HttpResponseRedirect`, `django.http.HttpResponsePermanentRedirect`, or the `django.shortcuts.redirect` shortcut. This triggers inefficient algorithmic complexity (CWE-407), leading to excessive CPU consumption and service exhaustion. The issue is fixed in versions 4.2.26, 5.1.14, and 5.2.8.

Affected products

  • Django Software Foundation Django < 4.2.26, >= 5.0a1, < 5.1.14, >= 5.2a1, < 5.2.8

Identifiers

  • CVE-2025-64458
  • GHSA-qw25-v68c-qjf3
  • PYSEC-2025-107

Timeline

  • 2025-11-05: disclosed
  • 2025-11-05: advisory
  • 2025-11-05: patched

References

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