The LookupGetterOrSetter function in js3250.dll in Mozilla Firefox before 3.5.14 and 3.6.x before 3.6.11, Thunderbird before 3.0.9 and 3.1.x before 3.1.5, and SeaMonkey before 2.0.9 does not properly support window.__lookupGetter__ function calls that lack arguments, which allows remote attackers to execute arbitrary code or cause a denial of service (incorrect pointer dereference and application crash) via vectors involving a "dangling pointer" and the JS_ValueToId function.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.