Mozilla have taken to their Security Blog to update users on a security vulnerability they've found in their latest version of Firefox, version 16. The company have stated that there is an update arriving on October 11 on Firefox for Windows, Mac and Linux.
This update should fix the problems with the security hole, which Mozilla have stated:
Mozilla is aware of a security vulnerability in the current release version of Firefox (version 16). We are actively working on a fix and plan to ship updates tomorrow. Firefox version 15 is unaffected.
The impact of the hole itself:
The vulnerability could allow a malicious site to potentially determine which websites users have visited and have access to the URL or URL parameters. At this time we have no indication that this vulnerability is currently being exploited in the wild.
For the meantime, Mozilla have cleared Firefox 16 from its current installer page.