The FV Flowplayer Video Player plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the comment text in all versions up to, and including, 7.5.49.7212 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires an administrator to have enabled the non-default 'Parse Vimeo and YouTube links' (parse_comments) plugin setting, and requires a submitted comment to be approved by an administrator before the payload is publicly delivered.