Heap-based buffer overflow in Mozilla Firefox before 47.0 and Firefox ESR 45.x before 45.2 allows remote attackers to execute arbitrary code via foreign-context HTML5 fragments, as demonstrated by fragments within an SVG element.

JIT code allocation can allow for a bypass of ASLR and DEP protections leading to potential memory corruption attacks. This vulnerability affects Thunderbird < 45.7, Firefox ESR < 45.7, and Firefox < 51.