Django security releases issued: 6.0.3, 5.2.12, and 4.2.29

CVE-2026-25673: Potential denial-of-service vulnerability in URLField via Unicode normalization on Windows

The django.forms.URLField form field's to_python() method used urllib.parse.urlsplit() to determine whether to prepend a URL scheme to the submitted value. On Windows, urlsplit() performs NFKC normalization (unicodedata.normalize), which can be disproportionately slow for large inputs containing certain characters.

URLField.to_python() now uses a simplified scheme detection, avoiding Unicode normalization entirely and deferring URL validation to the appropriate layers. As a result, while leading and trailing whitespace is still stripped by default, characters such as newlines, tabs, and other control characters within the value are no longer handled by URLField.to_python(). When using the default URLValidator, these values will continue to raise ValidationError during validation, but if you rely on custom validators, ensure they do not depend on the previous behavior of URLField.to_python().

This issue has severity "moderate" according to the Django Security Policy.

Thanks to Seokchan Yoon for the report.

CVE-2026-25674: Potential incorrect permissions on newly created file system objects

Django's file-system storage and file-based cache backends used the process umask to control permissions when creating directories. In multi-threaded environments, one thread's temporary umask change can affect other threads' file and directory creation, resulting in file system objects being created with unintended permissions.

Django now applies the requested permissions via os.chmod() after os.mkdir(), removing the dependency on the process-wide umask.

This issue has severity "low" according to the Django Security Policy.

Thanks to Tarek Nakkouch for the report.

Affected supported versions

• Django main
• Django 6.0
• Django 5.2
• Django 4.2

Resolution

Patches to resolve the issue have been applied to Django's main, 6.0, 5.2, and 4.2 branches. The patches may be obtained from the following changesets.

The following releases have been issued

• Django 6.0.3 (download Django 6.0.3 | 6.0.3 checksums)
• Django 5.2.12 (download Django 5.2.12 | 5.2.12 checksums)
• Django 4.2.29 (download Django 4.2.29 | 4.2.29 checksums)

The PGP key ID used for this release is Natalia Bidart: 2EE82A8D9470983E

General notes regarding security reporting

As always, we ask that potential security issues be reported via private email to security@djangoproject.com, and not via Django's Trac instance, nor via the Django Forum. Please see our security policies for further information.