CVE-2006-3677: Undefined Security Weakness

Mozilla Firefox 1.5 before 1.5.0.5 and SeaMonkey before 1.0.3 allows remote attackers to execute arbitrary code by changing certain properties of the window navigator object window.navigator that are accessed when Java starts up, which causes a crash that leads to code execution...

Javascript navigator Object Vulnerability — Mozilla

An anonymous researcher for TippingPoint and the Zero Day Initiative showed that when used in a web page Java would reference properties of the window.navigator object as it started up. If the page replaced the navigator object before starting Java then the browser would crash in a way that could...