MEDIUM
Squid 3.4.4 through 3.4.11 and 3.5.0.1 through 3.5.1, when Digest authentication is used, allow remote authenticated users to retain access by leveraging a stale nonce, aka "Nonce replay vulnerability."
http://bugs.squid-cache.org/show_bug.cgi?id=4066
http://lists.opensuse.org/opensuse-updates/2015-10/msg00052.html
http://www.openwall.com/lists/oss-security/2015/10/01/1