DataDump is a MediaWiki extension that provides dumps of wikis. Prior to commit 67a82b76e186925330b89ace9c5fd893a300830b, DataDump had no protection against CSRF attacks so requests to generate or delete dumps could be forged. The vulnerability was patched in commit 67a82b76e186925330b89ace9c5fd893a300830b. There are no known workarounds. You must completely disable DataDump.