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Fencer Vulns
high 7.5

CVE-2026-25673 json

Potential denial-of-service vulnerability in URLField via Unicode normalization on Windows

published 2026-03-03 8 mo ago modified 2026-09-10 59 d ago also BIT-django-2026-25673 , EUVD-2026-9294 , GHSA-8p8v-wh79-9r56 , PYSEC-2026-2448

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

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.

Patch / fix

  • pypi django 4.2.29, 5.2.12, 6.0.3
  • bitnami django 4.2.29, 5.2.12, 6.0.3
  • djangoproject Django 4.2.29, 5.2.12, 6.0.3
  • py3-django Alpine 3.23 4.2.29-r0

alpine advisories ALPINE-CVE-2026-25673

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-25673 updated cvss 7.5

django: Django: Denial of Service via slow URL normalization on Windows

  • Red Hat Ansible Automation Platform 2 automation-controller, ansible-automation-platform-26/hub-rhel9, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, ansible-automation-platform-26/controller-rhel9, +4 more Red Hat Discovery 2 discovery/discovery-server-rhel9 Red Hat Satellite 6 satellite/iop-advisor-backend-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi django
>=6.0, <6.0.3
>=5.2, <5.2.12
>=4.2, <4.2.29
6.0.3
5.2.12
4.2.29
bitnami django
>=4.2.0, <4.2.29
>=5.2.0, <5.2.12
>=6.0.0, <6.0.3
4.2.29
5.2.12
6.0.3

Affected products

  • djangoproject Django
  • Red Hat Red Hat Ansible Automation Platform 2
  • Red Hat Red Hat Discovery 2
  • Red Hat Red Hat Satellite 6

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-770 Allocation of Resources Without Limits or Throttling
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.