Disclosure Date: April 28, 2021 (last updated May 08, 2021)
ManageWiki is an extension to the MediaWiki project. The 'wikiconfig' API leaked the value of private configuration variables set through the ManageWiki variable to all users. This has been patched by https://github.com/miraheze/ManageWiki/compare/99f3b2c8af18...befb83c66f5b.patch. If you are unable to patch set `$wgAPIListModules['wikiconfig'] = 'ApiQueryDisabled';` or remove private config as a workaround.