Due to an improper input validation bug, Squid is vulnerable to a heap-based buffer overflow attack against cache digests.

This problem allows a trusted server to perform a heap-based buffer overflow when sending maliciously crafted replies to cache_digest request messages.

This attack is limited to Squid instances that have been compiled with the --enable-cache-digests option. Trusted peers are expected to be servers within the same administrative domain. As cache digests are exchanged over TCP, there is no risk of spoofing.