http-cache-semantics through 4.2.0 fails to properly validate security-zeroed cache entries when processing client max-stale directives, allowing unauthenticated attackers to retrieve cached responses belonging to other users. Attackers can request the same URL with a large max-stale value to obtain another users Set-Cookie session credentials from shared-cache entries that were deliberately zeroed for security reasons.
Weakness
The code uses a cache that contains sensitive information, but the cache can be read by an actor outside of the intended control sphere.
Potential Mitigations
Related Attack Patterns
References
- https://github.com/kornelski/http-cache-semantics
- https://github.com/kornelski/http-cache-semantics/blob/f01112e954b83cfa8765b633ba880e5e980aa54c/index.js#L425-L441
- https://github.com/kornelski/http-cache-semantics/blob/f01112e954b83cfa8765b633ba880e5e980aa54c/index.js#L603-L623
- https://github.com/kornelski/http-cache-semantics/issues/56
- https://www.vulncheck.com/advisories/http-cache-semantics-through-4.2.0-cross-user-cache-disclosure-via-max-stale
- https://github.com/kornelski/http-cache-semantics/issues/56