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

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-25673
StatePUBLISHED
AssignerDSF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-03 15:16:19 UTC
Updated2026-06-30 03:17:43 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-400 | CWE-770 | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-770 Allocation of Resources Without Limits or Throttling

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1ADPCVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Djangoproject Django All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Djangoproject Django affected 6.0 6.0.3 semver Not specified
CNA Djangoproject Django unaffected 6.0.3 semver Not specified
CNA Djangoproject Django affected 5.2 5.2.12 semver Not specified
CNA Djangoproject Django unaffected 5.2.12 semver Not specified
CNA Djangoproject Django affected 4.2 4.2.29 semver Not specified
CNA Djangoproject Django unaffected 4.2.29 semver Not specified
ADP Red Hat Red Hat Ansible Automation Platform 2 Not specified Not specified
ADP Red Hat Red Hat Discovery 2 Not specified Not specified
ADP Red Hat Red Hat Satellite 6 Not specified Not specified

References

ReferenceSourceLinkTags
access.redhat.com/security/cve/CVE-2026-25673 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25673.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com
groups.google.com/g/django-announce 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92 groups.google.com Release Notes
docs.djangoproject.com/en/dev/releases/security 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92 docs.djangoproject.com Patch, Vendor Advisory
www.djangoproject.com/weblog/2026/mar/03/security-releases 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92 www.djangoproject.com Patch, Vendor Advisory
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Seokchan Yoon (en)

CNA: Natalia Bidart (en)

CNA: Natalia Bidart (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-01-27T12:00:00.000ZInitial report received.
CNA2026-02-20T12:00:00.000ZVulnerability confirmed.
CNA2026-03-03T08:00:00.000ZSecurity release issued.
ADP2026-03-03T15:01:31.969ZReported to Red Hat.
ADP2026-03-03T14:28:28.601ZMade public.
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