Squid 2.5 up to 2.5.STABLE7 allows remote attackers to poison the cache or conduct certain attacks via headers that do not follow the HTTP specification, including (1) multiple Content-Length headers, (2) carriage return (CR) characters that are not part of a CRLF pair, and (3) header names containing whitespace characters.

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.

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.

The clientAbortBody function in client_side.c in Squid Web Proxy Cache before 2.6 STABLE6 allows remote attackers to cause a denial of service (segmentation fault) via unspecified vectors that trigger a null dereference. NOTE: in a followup advisory, a researcher claimed that the issue was a buffer overflow that was not fixed in STABLE6. However, the vendor's bug report clearly shows that the researcher later retracted this claim, because the tested product was actually STABLE5.

Buffer overflow in the ntlm_check_auth (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).

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.