Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
mail-archives.apache.org/mod_mbox/tomcat-announce/201112.mbox/%[email protected]%3e
marc.info/?l=bugtraq&m=132871655717248&w=2
marc.info/?l=bugtraq&m=133294394108746&w=2
marc.info/?l=bugtraq&m=136485229118404&w=2
rhn.redhat.com/errata/RHSA-2012-0074.html
rhn.redhat.com/errata/RHSA-2012-0075.html
rhn.redhat.com/errata/RHSA-2012-0076.html
tomcat.apache.org/tomcat-7.0-doc/changelog.html
www.debian.org/security/2012/dsa-2401
www.kb.cert.org/vuls/id/903934
www.nruns.com/_downloads/advisory28122011.pdf
www.ocert.org/advisories/ocert-2011-003.html
bugzilla.redhat.com/show_bug.cgi?id=750521
github.com/apache/tomcat
github.com/FireFart/HashCollision-DOS-POC/blob/master/HashtablePOC.py
nvd.nist.gov/vuln/detail/CVE-2011-4858
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18886