Mozilla Firefox before 24.0, Firefox ESR 17.x before 17.0.9, Thunderbird before 24.0, Thunderbird ESR 17.x before 17.0.9, and SeaMonkey before 2.21 do not properly handle movement of XBL-backed nodes between documents, which allows remote attackers to execute arbitrary code or cause a denial of service (JavaScript compartment mismatch, or assertion failure and application exit) via a crafted web site.
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.