Use-after-free vulnerability in the ~nsHTMLEditRules implementation in
Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and 17.x
before 17.0.1, Thunderbird before 17.0.2, Thunderbird ESR 10.x before
10.0.12 and 17.x before 17.0.1, and SeaMonkey before 2.15 allows remote
attackers to execute arbitrary code or cause a denial of service (heap
memory corruption) via unspecified vectors.