Ubuntu Security Notice 6515-1 - Multiple security issues were discovered in Thunderbird. If a user were tricked into opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, bypass security restrictions, cross-site tracing, or execute arbitrary code. It was discovered that Thunderbird did not properly manage memory when images were created on the canvas element. An attacker could potentially exploit this issue to obtain sensitive information.