Squid 2.5 up to 2.5.STABLE7 allows remote attackers to poison the cache via an HTTP response splitting attack.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11605
http://www.squid-cache.org/Versions/v2/2.5/bugs/#squid-2.5.STABLE7-response_splitting
http://www.squid-cache.org/Advisories/SQUID-2005_5.txt
http://www.securityfocus.com/bid/12433
http://www.redhat.com/support/errata/RHSA-2005-061.html
http://www.redhat.com/support/errata/RHSA-2005-060.html
http://www.redhat.com/archives/fedora-announce-list/2005-May/msg00025.html
http://www.novell.com/linux/security/advisories/2005_06_squid.html
http://www.mandriva.com/security/advisories?name=MDKSA-2005:034
http://www.kb.cert.org/vuls/id/625878
http://www.debian.org/security/2005/dsa-667
http://marc.info/?l=bugtraq&m=110780531820947&w=2
http://fedoranews.org/updates/FEDORA--.shtml
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000931