The Mozzarella Foundation has issued a warning that some versions of FireFox, Thunderbird and SeaMonkey needs a patch.

The bug, described as "critical" means that your software will crash with evidence of memory corruption.

MozarellaThe problem has already been fixed in some versions of FireFix, Thunderbird and SeaMonkey - and there is a workaround.

You can disable Javascript until a version containing these fixes can be installed.

The bug was found by Mozilla developers. The advice says: "We presume that with enough effort, at leastsome of these could be exploited to run arbitrary code".

The advice is here.