This indicates an attack attempt against an arbitrary Code Execution in the Mozilla Firefox.
The vulnerability is caused by an error due to the way XPCOM is implemented in Mozilla firefox. It allows a remote attacker to execute arbitrary code via a crafted web page.
Mozilla Foundation Firefox 0.8 - 1.0
Mozilla Foundation Mozilla Suite 1.0 - 1.7.5
System Compromise: Remote attackers can gain control of vulnerable systems.
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