CVE-2026-25673
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
An issue was discovered in 6.0 before 6.0.3, 5.2 before 5.2.12, and 4.2 before 4.2.29.
URLField.to_python() in Django calls urllib.parse.urlsplit(), which performs NFKC normalization on Windows that is disproportionately slow for certain Unicode characters, allowing a remote attacker to cause denial of service via large URL inputs containing these characters.
Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected.
Django would like to thank Seokchan Yoon for reporting this issue.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| djangoproject | Django | 6.0 < 6.0.3 | affected |
| djangoproject | Django | 6.0.3 | unaffected |
| djangoproject | Django | 5.2 < 5.2.12 | affected |
| djangoproject | Django | 5.2.12 | unaffected |
| djangoproject | Django | 4.2 < 4.2.29 | affected |
| djangoproject | Django | 4.2.29 | unaffected |
Weaknesses
- CWE-400: CWE-400: Uncontrolled Resource Consumption
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: yes
- Technical Impact: partial
django: Django: Denial of Service via slow URL normalization on Windows
Additional References
- https://access.redhat.com/security/cve/CVE-2026-25673
- https://bugzilla.redhat.com/show_bug.cgi?id=2444115
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25673.json
References
- https://docs.djangoproject.com/en/dev/releases/security/
- https://groups.google.com/g/django-announce
- https://www.djangoproject.com/weblog/2026/mar/03/security-releases/
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