Ubuntu Security Notice 2552-1 – Olli Pettay and Boris Zbarsky discovered an issue during anchor navigations in some circumstances. If a user were tricked in to opening a specially crafted message with scripting enabled, an attacker could potentially exploit this to bypass same-origin policy restrictions. Christoph Kerschbaumer discovered that CORS requests from navigator.sendBeacon() followed 30x redirections after preflight. If a user were tricked in to opening a specially crafted message with scripting enabled, an attacker could potentially exploit this to conduct cross-site request forgery (XSRF) attacks. Various other issues were also addressed.