MediaWiki 1.8.1, and other versions before 1.13.3, when the wgShowExceptionDetails variable is enabled, sometimes provides the full installation path in a debugging message, which might allow remote attackers to obtain sensitive information via unspecified requests that trigger an uncaught exception.
https://www.redhat.com/archives/fedora-package-announce/2008-December/msg01309.html
https://www.redhat.com/archives/fedora-package-announce/2008-December/msg01256.html
http://www.mediawiki.org/wiki/Manual:%24wgShowExceptionDetails
http://secunia.com/advisories/33349
http://lists.wikimedia.org/pipermail/mediawiki-announce/2008-December/000080.html