Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. Prior to version 7.2.0, `Special:URIResolver` resolves its user-controll…

Summary

Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. Prior to version 7.2.0, `Special:URIResolver` resolves its user-controlled subpage to a MediaWiki title and issues an HTTP 303 redirect to `$title->getFullURL()` without validating the resolved target. A crafted subpage can make that target point off-host: an interwiki prefix redirects to the foreign wiki (for example `Special:URIResolver/mw-3AFoo`, which decodes to `mw…