CVE-2024-34502: mediawiki: MergeLexemes makes edits on GET requests without edit tokens

Severity: Critical

CVSS Score: 9.8

An issue was discovered in WikibaseLexeme in MediaWiki before 1.39.6, 1.40.x before 1.40.2, and 1.41.x before 1.41.1. Loading Special:MergeLexemes will (attempt to) make an edit that merges the from-id to the to-id, even if the request was not a POST request, and even if it does not contain an edit token.