The SVGTextElement.getCharNumAtPosition function in Mozilla Firefox before 3.6.20, and 4.x through 5; Thunderbird 3.x before 3.1.12 and other versions before 6; SeaMonkey 2.x before 2.3; and possibly other products does not properly handle SVG text, which allows remote attackers to execute arbitrary code via unspecified vectors that lead to a "dangling pointer."