On October 10th, in a security notice Canonical published details about devscripts vulnerabilities for its Ubuntu 12.04 LTS, Ubuntu 11.10, Ubuntu 11.04, and Ubuntu 10.04 LTS operating systems.
According to Canonical, several security issues were fixed in Mozilla Firefox, such as several memory corruption flaws, improper handling of HTML5 specifications, improper security checks on tests methods for DOMWindowUtils, and many others
A remote attacker could have cause Firefox to crash, execute arbitrary code as the user invoking the program, conduct URL spoofing and clickjacking attack, intercept posted data, and conduct cross-site scripting (XSS) attacks.
The security flaws can be fixed if you upgrade your system(s) to the latest Firefox 16.0 package, specific to each operating system. To apply the update, run the Update Manager application.
In general, a standard system update will make all the necessary changes. A system restart won't be necessary to implement the changes.