A buffer over-read was discovered in libntlmauth in Squid 2.5 through 5.6. Due to incorrect integer-overflow protection, the SSPI and SMB authentication helpers are vulnerable to reading unintended memory locations. In some configurations, cleartext credentials from these locations are sent to a client. This is fixed in 5.7.
https://www.openwall.com/lists/oss-security/2022/09/23/2
https://github.com/squid-cache/squid/security/advisories/GHSA-394c-rr7q-6g78
http://www.squid-cache.org/Versions/v5/changesets/SQUID-2022_2.patch
http://www.squid-cache.org/Versions/v4/changesets/SQUID-2022_2.patch