The CleanChanges extension for MediaWiki before 1.19.9, 1.20.x before 1.20.8, and 1.21.x before 1.21.3, when "Group changes by page in recent changes and watchlist" is enabled, allows remote attackers to obtain sensitive information (revision-deleted IPs) via the Recent Changes page.
api.php in MediaWiki before 1.15.5 does not prevent use of public caching headers for private data, which allows remote attackers to bypass intended access restrictions and obtain sensitive information by retrieving documents from an HTTP proxy cache that has been used by a victim.
The Scribunto extension for MediaWiki allows remote attackers to obtain the rollback token and possibly other sensitive information via a crafted module, related to unstripping special page HTML.
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.
The (1) Special:MyPage, (2) Special:MyTalk, (3) Special:MyContributions, (4) Special:MyUploads, and (5) Special:AllMyUploads pages in MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1 allow remote attackers to obtain sensitive user login information via crafted links combined with page view statistics.