Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation Mediawiki - GlobalBlocking Extension allows Retrieve Embedded Sensitive Data. This issue briefly impacted the master branch of MediaWiki’s GlobalBlocking Extension.
https://phabricator.wikimedia.org/T377855
https://gerrit.wikimedia.org/r/q/I2a2d32aedf6328be0a9f1b4e04a6567a25f19486