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.
Conclusion & alert: CVE-2014-8638 is rated Moderate Risk (50.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.50%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-12-04 | 0.18% | 0.50% | +0.32% |
| 2 | 2025-03-17 | 0.64% | 0.18% | -0.46% |
| 3 | 2024-08-26 | — | 0.64% | — |
Full EPSS history (6 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.8 | 2.0 | MEDIUM |
|
8.6 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
gentoo
|
normal | CVE-2014-8638: 1 GLSA(s) (201504-01), 7 atom(s) (dev-libs/nspr, mail-client/thunderbird, …); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2014-8638 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2014-8638 |
suse
|
medium | CVE-2014-8638 severity moderate: SUSE including 149 source package names (MozillaFirefox, MozillaFirefox-102.11.0-150200.152.87.1, …), 319 product×package rows across 81 product lines (Image SLES12-SP5-Azure-BYOS, Image SLES12-SP5-Azure-Basic-On-Demand, … (81 product lines)): Fixed 288, Known Not Affected 31. | https://www.suse.com/security/cve/CVE-2014-8638/ |
ubuntu
|
medium | CVE-2014-8638 medium priority: Ubuntu including 2 source packages (firefox, thunderbird), 10 status rows across 5 suites (lucid, precise, trusty, upstream, utopic): released 8, ignored 2. | https://ubuntu.com/security/CVE-2014-8638 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mozilla | firefox | 31.0 | cpe:2.3:a:mozilla:firefox:31.0:*:*:*:*:*:*:* |
| mozilla | firefox | 31.1.0 | cpe:2.3:a:mozilla:firefox:31.1.0:*:*:*:*:*:*:* |
| mozilla | firefox | 31.1.1 | cpe:2.3:a:mozilla:firefox:31.1.1:*:*:*:*:*:*:* |
| mozilla | firefox | 31.3.0 | cpe:2.3:a:mozilla:firefox:31.3.0:*:*:*:*:*:*:* |
| mozilla | firefox_esr | 31.2 | cpe:2.3:a:mozilla:firefox_esr:31.2:*:*:*:*:*:*:* |
| mozilla | thunderbird | <= 31.3.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| mozilla | firefox | <= 34.0.5 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* |
| mozilla | seamonkey | <= 2.31 | cpe:2.3:a:mozilla:seamonkey:*:*:*:*:*:*:*:* |