Use-after-free vulnerability in Mozilla Firefox before 3.6.26 and 4.x through 9.0, Thunderbird before 3.1.18 and 5.0 through 9.0, and SeaMonkey before 2.7 might allow remote attackers to execute arbitrary code via vectors related to incorrect AttributeChildRemoved notifications that affect access to removed nsDOMAttribute child nodes.

Mozilla Firefox before 3.6.26 and 4.x through 6.0, Thunderbird before 3.1.18 and 5.0 through 6.0, and SeaMonkey before 2.4 do not properly enforce the IPv6 literal address syntax, which allows remote attackers to obtain sensitive information by making XMLHttpRequest calls through a proxy and reading the error messages.