Mozilla Firefox before 3.0.19 3.5.x before 3.5.9 and 3.6.x before 3.6.2 and SeaMonkey before 2.0.4 frees the contents of the window.navigator.plugins array while a reference to an array element is still active which allows remote attackers to execute arbitrary code or cause a denial of service (application crash) via unspecified vectors related to a \dangling pointer vulnerability.\