An issue was discovered in Django 6.1 before 6.1.2, 6.0 before 6.0.9, and 5.2 before 5.2.18. `django.utils.http.parse_header_parameters()` was subject to a potential denial-of-service attack due to quadratic time complexity when parsing a value with many separators inside a quoted parameter. An unauthenticated request could reach this parsing through headers such as `Accept` or `Content-Type`, for instance via the content negotiation performed by `HttpRequest.accepts()`. The per-call length limit does not bound the combined size of repeated headers. Earlier, unsupported Django series (such as 5.1.x, 5.0.x, and 4.2.x) were not evaluated and may also be affected. Django would like to thank Jisung Chae for reporting this issue.
History

Wed, 07 Oct 2026 07:15:00 +0000

Type Values Removed Values Added
First Time appeared Djangoproject
Djangoproject django
Vendors & Products Djangoproject
Djangoproject django

Wed, 07 Oct 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-400
References
Metrics threat_severity

None

threat_severity

Moderate


Tue, 06 Oct 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 06 Oct 2026 13:45:00 +0000

Type Values Removed Values Added
Description An issue was discovered in Django 6.1 before 6.1.2, 6.0 before 6.0.9, and 5.2 before 5.2.18. `django.utils.http.parse_header_parameters()` was subject to a potential denial-of-service attack due to quadratic time complexity when parsing a value with many separators inside a quoted parameter. An unauthenticated request could reach this parsing through headers such as `Accept` or `Content-Type`, for instance via the content negotiation performed by `HttpRequest.accepts()`. The per-call length limit does not bound the combined size of repeated headers. Earlier, unsupported Django series (such as 5.1.x, 5.0.x, and 4.2.x) were not evaluated and may also be affected. Django would like to thank Jisung Chae for reporting this issue.
Title Potential denial-of-service vulnerability in HTTP header parsing
Weaknesses CWE-407
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: DSF

Published: 2026-10-06T13:35:17.443Z

Updated: 2026-10-06T14:15:10.916Z

Reserved: 2026-09-01T18:34:27.131Z

Link: CVE-2026-84429

cve-icon Vulnrichment

Updated: 2026-10-06T14:15:05.715Z

cve-icon NVD

Status : Deferred

Published: 2026-10-06T14:17:46.910

Modified: 2026-10-06T15:17:19.860

Link: CVE-2026-84429

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-06T14:21:00Z

Links: CVE-2026-84429 - Bugzilla