Squid, when transparent interception mode is enabled, uses the HTTP Host header to determine the remote endpoint, which allows remote attackers to bypass access controls for Flash, Java, Silverlight, and probably other technologies, and possibly communicate with restricted intranet sites, via a crafted web page that causes a client to send HTTP requests with a modified Host header.
Squid 2.7 to 2.7.STABLE5, 3.0 to 3.0.STABLE12, and 3.1 to 3.1.0.4 allows remote attackers to cause a denial of service via an HTTP request with an invalid version number, which triggers a reachable assertion in (1) HttpMsg.c and (2) HttpStatusLine.c.
The arrayShrink function (lib/Array.c) in Squid 2.6.STABLE17 allows attackers to cause a denial of service (process exit) via unknown vectors that cause an array to shrink to 0 entries, which triggers an assert error. NOTE: this issue is due to an incorrect fix for CVE-2007-6239.
The "cache update reply processing" functionality in Squid 2.x before 2.6.STABLE17 and Squid 3.0 allows remote attackers to cause a denial of service (crash) via unknown vectors related to HTTP headers and an Array memory leak during requests for cached objects.
The clientProcessRequest() function in src/client_side.c in Squid 2.6 before 2.6.STABLE12 allows remote attackers to cause a denial of service (daemon crash) via crafted TRACE requests that trigger an assertion error.
The aclMatchExternal function in Squid before 2.6.STABLE7 allows remote attackers to cause a denial of service (crash) by causing an external_acl queue overload, which triggers an infinite loop.
squid/src/ftp.c in Squid before 2.6.STABLE7 allows remote FTP servers to cause a denial of service (core dump) via crafted FTP directory listing responses, possibly related to the (1) ftpListingFinish and (2) ftpHtmlifyListEntry functions.
The rfc1738_do_escape function in ftp.c for Squid 2.5 STABLE11 and earlier allows remote FTP servers to cause a denial of service (segmentation fault) via certain "odd" responses.
Squid 2.5.STABLE10 and earlier, while performing NTLM authentication, does not properly handle certain request sequences, which allows attackers to cause a denial of service (daemon restart).
store.c in Squid 2.5.STABLE10 and earlier allows remote attackers to cause a denial of service (crash) via certain aborted requests that trigger an assert error related to STORE_PENDING.
The sslConnectTimeout function in ssl.c for Squid 2.5.STABLE10 and earlier allows remote attackers to cause a denial of service (segmentation fault) via certain crafted requests.
Gibraltar Firewall 2.2 and earlier, when using the ClamAV update to 0.81 for Squid, uses a defunct ClamAV method to scan memory for viruses, which does not return an error code and prevents viruses from being detected.
Squid 2.5 STABLE9 and earlier, when the DNS client port is unfiltered and the environment does not prevent IP spoofing, allows remote attackers to spoof DNS lookups.
squid_ldap_auth in Squid 2.5 and earlier allows remote authenticated users to bypass username-based Access Control Lists (ACLs) via a username with a space at the beginning or end, which is ignored by the LDAP server.
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.
The httpProcessReplyHeader function in http.c for Squid 2.5-STABLE7 and earlier does not properly set the debug context when it is handling "oversized" HTTP reply headers, which might allow remote attackers to poison the cache or bypass access controls based on header size.
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.STABLE9 and earlier does not trigger a fatal error when it identifies missing or invalid ACLs in the http_access configuration, which could lead to less restrictive ACLs than intended by the administrator.
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.