Unspecified vulnerability the edit comment formatting functionality in MediaWiki 1.5.x before 1.5.6 and 1.4.x before 1.4.14 allows attackers to cause a denial of service (infinite loop) via "certain malformed links."
https://exchange.xforce.ibmcloud.com/vulnerabilities/24478
http://www.vupen.com/english/advisories/2006/0392
http://sourceforge.net/project/shownotes.php?release_id=386609
http://secunia.com/advisories/18717
http://secunia.com/advisories/18711
http://lists.suse.com/archive/suse-security-announce/2006-Feb/0001.html