Vulnerability · Published Oct 6, 2026 · Assigned by DSF
CVE-2026-84429Potential denial-of-service vulnerability in HTTP header parsing
Medium 5.3
In plain English
A medium-severity security flaw in Django from djangoproject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | py3-django | 5.2.18-r0 | ALPINE-CVE-2026-84429 |
| Debian:12 | python-django | no fix listed | DEBIAN-CVE-2026-84429 |
| Debian:13 | python-django | no fix listed | DEBIAN-CVE-2026-84429 |
| Debian:14 | python-django | no fix listed | DEBIAN-CVE-2026-84429 |
| Ubuntu:22.04:LTS | python-django | no fix listed | UBUNTU-CVE-2026-84429 |
| Ubuntu:24.04:LTS | python-django | no fix listed | UBUNTU-CVE-2026-84429 |
| Ubuntu:26.04:LTS | python-django | no fix listed | UBUNTU-CVE-2026-84429 |
| Ubuntu:26.10 | python-django | no fix listed | UBUNTU-CVE-2026-84429 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| djangoproject | Django | 6.1 – before 6.1.26.0 – before 6.0.95.2 – before 5.2.18 |
Weakness: CWE-407 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
- Django security archive vendor-advisory
- Django releases announcements mailing-list
- https://github.com/django/django/commit/7ff7fcc0508864a4bc39693128ace38b1e95a890 patch
- https://github.com/django/django/commit/de56deeabd4c48dfb5193f0001469d80102fb367 patch
- https://github.com/django/django/commit/3d8f121695c21234aff3071de0d38b6bd38c3f52 patch
- https://github.com/django/django/commit/6ecd66e09a383be004a78a3a738ea9727ff07b0e patch
- Django security releases issued: 6.1.2, 6.0.9, and 5.2.18 vendor-advisory