Squid 3.0 through 3.0.STABLE16 and 3.1 through 3.1.0.11 allows remote attackers to cause a denial of service via malformed requests including (1) “missing or mismatched protocol identifier,” (2) missing or negative status value," (3) “missing version,” or (4) “missing or invalid status number,” related to (a) HttpMsg.cc and (b) HttpReply.cc.
secunia.com/advisories/36007
www.mandriva.com/security/advisories?name=MDVSA-2009:161
www.mandriva.com/security/advisories?name=MDVSA-2009:178
www.securityfocus.com/bid/35812
www.securitytracker.com/id?1022607
www.squid-cache.org/Advisories/SQUID-2009_2.txt
www.squid-cache.org/Versions/v3/3.1/changesets/b9661.patch
www.vupen.com/english/advisories/2009/2013