MediaWiki before 1.17.1 allows remote attackers to obtain the page titles of all restricted pages via a series of requests involving the (1) curid or (2) oldid parameter.
https://bugzilla.wikimedia.org/show_bug.cgi?id=32276
https://bugzilla.redhat.com/show_bug.cgi?id=758171
http://www.debian.org/security/2011/dsa-2366
http://openwall.com/lists/oss-security/2011/11/29/6
http://openwall.com/lists/oss-security/2011/11/29/12
http://lists.wikimedia.org/pipermail/mediawiki-announce/2011-November/000104.html