Livemarks is a browser extension that provides RSS feed bookmark folders. Versions of Livemarks prior to 3.7 are vulnerable to cross-site request forgery. A malicious website may be able to coerce the extension to send an authenticated GET request to an arbitrary URL. An authenticated request is a request where the cookies of the browser are sent along with the request. The `subscribe.js` script uses the first parameter from the current URL location as the URL of the RSS feed to subscribe to and checks that the RSS feed is valid XML. `subscribe.js` is accessible by an attacker website due to its use in `subscribe.html`, an HTML page that is declared as a `web_accessible_resource` in `manifest.json`. This issue may lead to `Privilege Escalation`. A CSRF breaks the integrity of servers running on a private network. A user of the browser extension may have a private server with dangerous functionality, which is assumed to be safe due to network segmentation. Upon receiving an authenticat…