Ubuntu Security Notice 2723-1 – A use-after-free was discovered when resizing a canvas element during restyling in some circumstances. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via application crash, or execute arbitrary code with the privileges of the user invoking Firefox. Bas Venis discovered that the addon install permission prompt could be bypassed using data: URLs in some circumstances. It was also discovered that the installation notification could be made to appear over another site. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to install a malicious addon. Various other issues were also addressed.