CVE-2026-84429

Name	CVE-2026-84429
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1150176

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
python-django (PTS)	bookworm	3:3.2.25-0+deb12u3	vulnerable
	bookworm (security)	3:3.2.25-0+deb12u6	vulnerable
	trixie	3:4.2.28-0+deb13u2	vulnerable
	trixie (security)	3:4.2.28-0+deb13u1	vulnerable
	forky	3:5.2.17-2	vulnerable
	sid	3:5.2.18-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-django	source	(unstable)	3:5.2.18-1			1150176

Notes

[bookworm] - python-django <ignored> (Invasive fix as it requires backporting another refactor, as well as adjusting the highly-finicky str/bytes distiction)
https://www.djangoproject.com/weblog/2026/oct/06/security-releases/
Fixed by: https://github.com/django/django/commit/6ecd66e09a383be004a78a3a738ea9727ff07b0e (5.2.18)