Stack-based buffer overflow in the text-rendering functionality 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 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a long argument to the document.write method.
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.