Mozilla Firefox 4.x through 9.0, Thunderbird 5.0 through 9.0, and SeaMonkey before 2.7 do not properly initialize data for image/vnd.microsoft.icon images, which allows remote attackers to obtain potentially sensitive information by reading a PNG image that was created through conversion from an ICO image.
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.
Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox 4.x through 9.0, Thunderbird 5.0 through 9.0, and SeaMonkey before 2.7 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown vectors.