# Django 5.2.17 documentation

# Django 5.2.12 release notes

March 3, 2026

Django 5.2.12 fixes a security issue with severity “moderate” and a security issue with severity “low” in 5.2.11. It also fixes one bug related to support for Python 3.14.

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

The `URLField` form field’s `to_python()` method used `urlsplit()` to determine whether to prepend a URL scheme to the submitted value. On Windows, `urlsplit()` performs `NFKC normalization`, 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.

## 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 `chmod()` after `mkdir()`, removing the dependency on the process-wide umask.

This issue has severity “low” according to the Django security policy.

## Bugfixes

- Fixed `NameError` when inspecting functions making use of deferred annotations in Python 3.14 (#36903).