Firefox could be made to crash or run programs as your login if it opened a malicious website.
It was discovered that Firefox contained a memory safety issue. If a user were tricked into opening a specially crafted page with the HTML editor, a remote attacker could exploit this to execute arbitrary code with the privileges of the user invoking the program.
8 March 2013
A security issue affects these releases of Ubuntu and its derivatives:
Firefox could be made to crash or run programs as your login if it opened a malicious website.
It was discovered that Firefox contained a memory safety issue. If a user were tricked into opening a specially crafted page with the HTML editor, a remote attacker could exploit this to execute arbitrary code with the privileges of the user invoking the program.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to restart Firefox to make all the necessary changes.