CVE-2026-84429
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. Limited direct impact.
- Exploit odds
- 0.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.5% in the next 30 days (EPSS).
- Severity: 6.9 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.5% · EPSS, next 30 days
- Weakness
- CWE-407
- Record status
- Deferred
Attack profile CVSS 4.0 · 6.9
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-84429.md and follow it. Check whether this project is affected by CVE-2026-84429. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- 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
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/