Software Engineering Institute

The Mozilla browser and derived products include support for Content Style Sheets (CSS). A vulnerability has been discovered in the way that these products handle the CSS border-rendering function. According to Mozilla Foundation Security Advisory 2006-11:

As part of the Firefox 1.5 release we fixed several crash bugs to improve the stability of the product. Some of these crashes showed evidence of memory corruption that we presume could be exploited to run arbitrary code and have been applied to the Firefox 1.0.x and Mozilla Suite 1.7.x releases.
While fixing an unexploitable recursion-induced crash Bernd Mielke discovered that the CSS border-rendering code could potentially write past the end of an array....Note: Thunderbird shares the browser engine with Firefox and could be vulnerable if JavaScript were to be enabled in mail. This is not the default setting and we strongly discourage users from running JavaScript in mail.

A remote attacker may be able to crash a vulnerable program or run code of their choosing on an affected system. The attacker-supplied code would be executed with the permissions of the user running the vulnerable program.

Upgrade

The Mozilla Foundation has published Mozilla Foundation Security Advisory 2006-11 in response to this issue. Users are encouraged to review this advisory and upgrade to the fixed versions of the products it describes.

Workarounds

Users, particularly those who are unable to upgrade to a fixed version of the software, are encouraged to disable JavaScript in the affected programs.