MediaWiki is a free and free-to-use web-based wiki engine from the U.S. Wikimedia (MediaWiki) Foundation. The product can be used to deploy internal knowledge management and content management systems.A security vulnerability exists in MediaWiki, which stems from the fact that the product allows non-privileged users to view confidential information (e.g., IP addresses and User-Agent headers for election traffic) on testwiki SecurePoll instances. No details of the vulnerability are currently available.