Django <5.2.15, <6.0.6: UpdateCacheMiddleware Cache-Control Case Sensitivity Flaw
CVE-2026-8404 Published on June 3, 2026
Potential exposure of private data via case-sensitive Cache-Control directives in UpdateCacheMiddleware
An issue was discovered in Django 5.2 before 5.2.15 and 6.0 before 6.0.6.
`django.middleware.cache.UpdateCacheMiddleware` in Django does not match `Cache-Control` response directives case-insensitively, which allows remote attackers to read responses that were incorrectly cached because their `Cache-Control` directives used uppercase or mixed-case values.
Earlier, unsupported Django series (such as 5.0.x, 4.1.x, and 3.2.x) were not evaluated and may also be affected.
Django would like to thank Ahmed Badawe for reporting this issue.
Timeline
Initial report received.
Vulnerability confirmed. 6 days later.
Security release issued. 22 days later.
Weakness Type
Improper Handling of Case Sensitivity
The software does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Products Associated with CVE-2026-8404
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Affected Versions
djangoproject Django:- Version 6.0 and below 6.0.6 is affected.
- Version 6.0.6 is unaffected.
- Version 5.2 and below 5.2.15 is affected.
- Version 5.2.15 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.