Buffer overflow in the ntlmcheckauth (NTLM authentication) function for Squid Web Proxy Cache 2.5.x and 3.x, when compiled with NTLM handlers enabled, allows remote attackers to execute arbitrary code via a long password ("pass" variable).

Squid Internet Object Cache 1.1.20 allows users to bypass access control lists (ACLs) by encoding the URL with hexadecimal escape sequences.

Squid 2.2.STABLE5 and below, when using external authentication, allows attackers to bypass access controls via a newline in the user/password pair.

Squid Web Proxy Cache 2.3.STABLE5 allows remote attackers to bypass security controls and access arbitrary websites via "@@" sequences in a URL within Internet Explorer.

Squid Web Proxy Cache 2.5 might allow remote attackers to obtain sensitive information via URLs containing invalid hostnames that cause DNS operations to fail, which results in references to previously used error messages.

squid 2.3 and earlier allows local users to overwrite arbitrary files via a symlink attack in some configurations.