Use-after-free vulnerability in the nsOverflowContinuationTracker::Finish function in Mozilla Firefox before 19.0, Firefox ESR 17.x before 17.0.3, Thunderbird before 17.0.3, Thunderbird ESR 17.x before 17.0.3, and SeaMonkey before 2.16 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via a crafted document that uses Cascading Style Sheets (CSS) -moz-column-* properties.