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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products
djangoproject:django
References 7
https://docs.djangoproject.com/en/dev/releases/security/
Django security archive
https://groups.google.com/g/django-announce
Django releases announcements
https://github.com/django/django/commit/7ff7fcc0508864a4bc39693128ace38b1e95a890
NVD
https://github.com/django/django/commit/de56deeabd4c48dfb5193f0001469d80102fb367
NVD
https://github.com/django/django/commit/3d8f121695c21234aff3071de0d38b6bd38c3f52
NVD
https://github.com/django/django/commit/6ecd66e09a383be004a78a3a738ea9727ff07b0e
NVD
https://www.djangoproject.com/weblog/2026/oct/06/security-releases/
Django security releases issued: 6.1.2, 6.0.9, and 5.2.18