The reset functionality in the TimedMediaHandler extension for MediaWiki does not create a new transcode, which allows remote attackers to cause a denial of service (transcode deletion) by resetting a transcode.
https://security.gentoo.org/glsa/201510-05
https://phabricator.wikimedia.org/T100211
https://lists.wikimedia.org/pipermail/mediawiki-announce/2015-August/000179.html
http://www.securityfocus.com/bid/76362
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