Red Hat Security Advisory RHSA-2004:134-01 – A bug was found in the processing of %-encoded characters in a URL in versions of Squid 2.5.STABLE4 and earlier. If a Squid configuration uses Access Control Lists (ACLs), a remote attacker could create URLs that would not be correctly tested against Squid’s ACLs, potentially allowing clients to access prohibited URLs.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/32972/RHSA-2004%3A134-01.txt
Source: https://packetstormsecurity.com/files/32972/RHSA-2004-134-01.txt.html