User interaction is required to exploit this vulnerability in that a user must be coerced to viewing a malicious document.
The specific flaw exists within the way the application implements the window.navigator.plugins array. Due to the application freeing the contents of the array while a reference to one of the elements is still being used, an attacker can utilize the free reference to call arbitrary code. Successful exploitation can lead to code execution under the context of the application.
Patch Availability:
Mozilla Firefox has issued an update to correct this vulnerability. More details can be found at:
http://www.mozilla.org/security/announce/2010/mfsa2010-19.html