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.