Buffer overflows in Squid before 2.4.STABLE6 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code (1) via the MSNT auth helper (msnt_auth) when using denyusers or allowusers files, (2) via the gopher client, or (3) via the FTP server directory listing parser when HTML output is generated.
FTP proxy in Squid before 2.4.STABLE6 does not compare the IP addresses of control and data connections with the FTP server, which allows remote attackers to bypass firewall rules or spoof FTP server responses.
Vulnerability in Squid before 2.4.STABLE6 related to proxy authentication credentials may allow remote web sites to obtain the user's proxy login and password.
Heap-based buffer overflow in Squid before 2.4 STABLE4, and Squid 2.5 and 2.6 until March 12, 2002 distributions, allows remote attackers to cause a denial of service, and possibly execute arbitrary code, via compressed DNS responses.
Squid 2.4 STABLE3 and earlier does not properly disable HTCP, even when "htcp_port 0" is specified in squid.conf, which could allow remote attackers to bypass intended access restrictions.
Squid 2.4 STABLE3 and earlier allows remote attackers to cause a denial of service (core dump) and possibly execute arbitrary code with an ftp:// URL with a larger number of special characters, which exceed the buffer when Squid URL-escapes the characters.