CVE-2026-84429
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…
Does this matter?
Lower severity and a low EPSS score (0.48%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 4.0
- 6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.48% probability · 41th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-407
- Source
- 6a34fbeb-21d4-45e7-8e0a-62b95bc12c92
EPSS moved from 0.4% on 7 October 2026 to 0.5% on 26 October 2026.
References
- https://docs.djangoproject.com/en/dev/releases/security/
- https://github.com/django/django/commit/3d8f121695c21234aff3071de0d38b6bd38c3f52
- https://github.com/django/django/commit/6ecd66e09a383be004a78a3a738ea9727ff07b0e
- https://github.com/django/django/commit/7ff7fcc0508864a4bc39693128ace38b1e95a890
- https://github.com/django/django/commit/de56deeabd4c48dfb5193f0001469d80102fb367
- https://groups.google.com/g/django-announce
- https://www.djangoproject.com/weblog/2026/oct/06/security-releases/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.