GeSHi, as used in the SyntaxHighlight_GeSHi extension and MediaWiki before 1.23.10, 1.24.x before 1.24.3, and 1.25.x before 1.25.2, allows remote attackers to cause a denial of service (resource consumption) via unspecified vectors.
https://security.gentoo.org/glsa/201510-05
https://phabricator.wikimedia.org/T101608
https://lists.wikimedia.org/pipermail/mediawiki-announce/2015-August/000179.html
http://www.securityfocus.com/bid/76361
http://www.openwall.com/lists/oss-security/2015/08/27/6
http://www.openwall.com/lists/oss-security/2015/08/12/6
http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165193.html