Dangling pointer vulnerability in LookupGetterOrSetter — Mozilla

Security researcher regenrecht reported via TippingPoint’s Zero Day Initiative that when window.lookupGetter is called with no arguments the code assumes the top JavaScript stack value is a property name. Since there were no arguments passed into the function, the top value could represent uninitialized memory or a pointer to a previously freed JavaScript object. Under such circumstances the value is passed to another subroutine which calls through the dangling pointer, potentially executing attacker-controlled memory.