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.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10998
https://exchange.xforce.ibmcloud.com/vulnerabilities/19060
http://www.squid-cache.org/bugs/show_bug.cgi?id=1216
http://www.squid-cache.org/Versions/v2/2.5/bugs/squid-2.5.STABLE7-oversize_reply_headers.patch
http://www.squid-cache.org/Versions/v2/2.5/bugs/#squid-2.5.STABLE7-oversize_reply_headers
http://www.securityfocus.com/bid/12412
http://www.redhat.com/support/errata/RHSA-2005-061.html
http://www.redhat.com/support/errata/RHSA-2005-060.html
http://www.novell.com/linux/security/advisories/2005_06_squid.html
http://www.kb.cert.org/vuls/id/823350
http://secunia.com/advisories/14091
http://fedoranews.org/updates/FEDORA--.shtml
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000931