CVE-2025-27556

MEDIUM

Django 5.0-5.0.13 and 5.1-5.1.7 - Denial of Service via NFKC Normalization on Windows

Title source: llm

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.

References (4)

Core 4

Core References

Vendor Advisory

https://docs.djangoproject.com/en/dev/releases/security/

Vendor Advisory

https://groups.google.com/g/django-announce

Vendor Advisory

https://www.djangoproject.com/weblog/2025/apr/02/security-releases/

Mailing List, Third Party Advisory

http://www.openwall.com/lists/oss-security/2025/04/02/2

Scores

CVSS v3 5.8

EPSS 0.0001

EPSS Percentile 1.5%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-770

Status published

Products (2)

djangoproject/django 5.0 - 5.0.14

pypi/Django 5.0 - 5.0.14PyPI

Published Apr 02, 2025

Tracked Since Feb 18, 2026