The nsHtml5TreeBuilder::resetTheInsertionMode function in the HTML5 Tree Builder in Mozilla Firefox before 24.0, Thunderbird before 24.0, and SeaMonkey before 2.21 does not properly maintain the state of the insertion-mode stack for template elements, which allows remote attackers to execute arbitrary code or cause a denial of service (heap-based buffer over-read) by triggering use of this stack in its empty state.

Use-after-free vulnerability in the mozilla::layout::ScrollbarActivity function in Mozilla Firefox before 24.0, Firefox ESR 17.x before 17.0.9, Thunderbird before 24.0, Thunderbird ESR 17.x before 17.0.9, and SeaMonkey before 2.21 allows remote attackers to execute arbitrary code via vectors related to image-document scrolling.