Squid 2.5, when processing the configuration file, parses empty Access Control Lists (ACLs), including proxy_auth ACLs without defined auth schemes, in a way that effectively removes arguments, which could allow remote attackers to bypass intended ACLs if the administrator ignores the parser warnings.

Squid 2.5.STABLE8 and earlier allows remote attackers to cause a denial of service (crash) via certain DNS responses regarding (1) Fully Qualified Domain Names (FQDN) in fqdncache.c or (2) IP addresses in ipcache.c, which trigger an assertion failure.

Squid 2.5.STABLE7 and earlier allows remote attackers to cause a denial of service (segmentation fault) by aborting the connection during a (1) PUT or (2) POST request, which causes Squid to access previously freed memory.

The asn_parse_header function (asn1.c) in the SNMP module for Squid Web Proxy Cache before 2.4.STABLE7 allows remote attackers to cause a denial of service (server restart) via certain SNMP packets with negative length fields that trigger a memory allocation error.

Memory leak in the NTLM fakeauth_auth helper for Squid 2.5.STABLE7 and earlier allows remote attackers to cause a denial of service (memory consumption).

The WCCP message parsing code in Squid 2.5.STABLE7 and earlier allows remote attackers to cause a denial of service (crash) via malformed WCCP messages with source addresses that are spoofed to reference Squid's home router and invalid WCCP_I_SEE_YOU cache numbers.

Buffer overflow in the gopherToHTML function in the Gopher reply parser for Squid 2.5.STABLE7 and earlier allows remote malicious Gopher servers to cause a denial of service (crash) via crafted responses.

The NTLM component in Squid 2.5.STABLE7 and earlier allows remote attackers to cause a denial of service (crash) via a malformed NTLM type 3 message that triggers a NULL dereference.

The "%xx" URL decoding function in Squid 2.5STABLE4 and earlier allows remote attackers to bypass url_regex ACLs via a URL with a NULL ("%00") character, which causes Squid to use only a portion of the requested URL when comparing it against the access control lists.

Opera 6.0.3, when using Squid 2.4 for HTTPS proxying, does not properly handle when accepting a non-global certificate authority (CA) certificate from a site and establishing a subsequent HTTPS connection, which allows remote attackers to cause a denial of service (crash).