Some vulnerabilities have been reported in Mozilla Firefox by Mozilla Developer and Community, which can be exploited by malicious people to disclose sensitive information, bypass certain security restrictions, or to compromise a vulnerable system. Some of these crashes showed evidence of memory corruption under certain circumstances and we presume that with enough effort at least some of these could be exploited to run arbitrary code.
Secunia Research has discovered a vulnerability in Firefox, which can be exploited by malicious people to potentially compromise a user’s system.

The vulnerability is caused due to a race condition when accessing the private data of an NPObject JS wrapper class object if navigating away from a web page while loading a Java applet. This can be exploited via a specially crafted web page to use already freed memory. Successful exploitation may allow execution of arbitrary code.

… continue reading : Mozilla Firefox Multiple Vulnerabilities.