Heap-based buffer overflow in the _cairo_pen_init function in Mozilla Firefox 2.x before 2.0.0.2, Thunderbird before 1.5.0.10, and SeaMonkey before 1.0.8 allows remote attackers to execute arbitrary code via a large stroke-width attribute in the clipPath element in an SVG file.
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.