CVE-2025-27556
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 0 |
| sid | Fixed | 0 |
| forky | Fixed | 0 |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-27556
- https://github.com/django/django/commit/2cb311f7b069723027fb5def4044d1816d7d2afd
- https://github.com/django/django/commit/39e2297210d9d2938c75fc911d45f0e863dc4821
- https://github.com/django/django/commit/8c6871b097b6c49d2a782c0d80d908bcbe2116f1
- https://github.com/django/django/commit/edc2716d01a6fdd84b173c02031695231bcee1f8
- https://docs.djangoproject.com/en/dev/releases/security
- https://github.com/django/django
- https://github.com/pypa/advisory-database/tree/main/vulns/django/PYSEC-2025-14.yaml
- https://groups.google.com/g/django-announce
- https://www.djangoproject.com/weblog/2025/apr/02/security-releases
- http://www.openwall.com/lists/oss-security/2025/04/02/2
- https://www.djangoproject.com/weblog/2025/apr/02/security-releases/
- https://docs.djangoproject.com/en/dev/releases/security/
- https://www.suse.com/security/cve/CVE-2025-27556.html
- https://security-tracker.debian.org/tracker/CVE-2025-27556
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.