CVE-2014-8638: Mozilla Firefox

Medium severity, CVSS 6.8. EPSS: 1% chance of exploitation in the next 30 days.

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.

Affected products

• Mozilla Firefox: version 31.0 only; version 31.1.0 only; version 31.1.1 only; version 31.3.0 only; up to and including 34.0.5
• Mozilla Firefox ESR: version 31.2 only
• Mozilla Seamonkey: up to and including 2.31
• Mozilla Thunderbird: up to and including 31.3.0

Published 2015-01-14. Last modified 2026-06-17.