Launchpad.net

CVE 2014-8638

The navigator.sendBeacon implementation in Mozilla Firefox before 35.0, Firefox ESR 31.x before 31.4, Thunderbird before 31.4, and SeaMonkey before 2.32 omits the CORS Origin header, which allows remote attackers to bypass intended CORS access-control checks and conduct cross-site request forgery (CSRF) attacks via a crafted web site.

See the CVE page on Mitre.org for more details.

References