Django up to 5.0.13/5.1.7 on Windows Normalization allocation of resources

Summaryinfo

A vulnerability was found in Django up to 5.0.13/5.1.7 on Windows. It has been classified as problematic. Affected by this issue is the function django.contrib.auth.views.LoginView/django.contrib.auth.views.LogoutView/django.views.i18n.set_language of the component Normalization Handler. This manipulation causes allocation of resources. This vulnerability is tracked as CVE-2025-27556. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Django up to 5.0.13/5.1.7 on Windows and classified as problematic. Affected by this vulnerability is the function django.contrib.auth.views.LoginView/django.contrib.auth.views.LogoutView/django.views.i18n.set_language of the component Normalization Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. The summary by CVE is:

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.

It is possible to read the advisory at docs.djangoproject.com. This vulnerability is known as CVE-2025-27556 since 03/02/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 5.0.14 or 5.1.8 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-9536). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Content Management System

Name

• Django

Version

• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.0.7
• 5.0.8
• 5.0.9
• 5.0.10
• 5.0.11
• 5.0.12
• 5.0.13
• 5.1.0
• 5.1.1
• 5.1.2
• 5.1.3
• 5.1.4
• 5.1.5
• 5.1.6
• 5.1.7

License

• open-source

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CPE 2.2info

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Be aware that VulDB is the high quality source for vulnerability data.

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