Mozilla Pulls Firefox 16 Update Offline After Discovering Security Flaw, Urges Users to Downgrade
"The vulnerability could allow a malicious site to potentially determine which websites users have visited and have access to the URL or URL parameters," Mozilla explained on its security blog. "At this time we have no indication that this vulnerability is currently being exploited in the wild."
Be that as it may, Mozilla was spooked enough to remove Firefox 16 from its installer page, which has been replaced with version 15.0.1. As a precaution, Mozilla says you can downgrade to the previous version.
"Alternatively, users can wait until our patches are issued and automatically applied to address the vulnerability," Mozilla added.
Whether you intended to upgrade or not, you might still be running Firefox 16. Mozilla recently switched to a silent update scheme that downloads new builds in the background and applies them when you restart your browser. To see which version you're running, click on the Firefox icon in the upper left-hand corner, expand the Help menu, and select About Firefox.