High severity · published Mar 3, 2026
CVE-2026-25673
Potential denial-of-service vulnerability in URLField via Unicode normalization on Windows
7.5
CVSS
0.8%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.8% · higher than 55% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DJ
Django · djangoproject
6.0 before 6.0.3; 5.2 before 5.2.12; 4.2 before 4.2.29 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-25673
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-25673
Patch
https://docs.djangoproject.com/en/dev/releases/security/
Release Notes
https://groups.google.com/g/django-announce
Patch
https://www.djangoproject.com/weblog/2026/mar/03/security-releases/
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-25673
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2444115
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25673.json
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