Buffer overflow in an unspecified string class in the WebGL shader implementation in Mozilla Firefox 4.x through 5, Thunderbird before 6, SeaMonkey 2.x before 2.3, and possibly other products allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via a long source-code block for a shader.
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.