CVE-2026-84429 is a vulnerability in Django Project Django
Published on October 6, 2026
Potential denial-of-service vulnerability in HTTP header parsing
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.
Timeline
Initial report received.
Vulnerability confirmed. 6 days later.
Security release issued. 35 days later.
Weakness Type
Inefficient Algorithmic Complexity
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
Products Associated with CVE-2026-84429
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Affected Versions
djangoproject Django:- Version 6.1 and below 6.1.2 is affected.
- Version 6.1.2 is unaffected.
- Version 6.0 and below 6.0.9 is affected.
- Version 6.0.9 is unaffected.
- Version 5.2 and below 5.2.18 is affected.
- Version 5.2.18 is unaffected.