The Chrome Object Wrapper (COW) implementation in Mozilla Firefox before 16.0, Firefox ESR 10.x before 10.0.8, Thunderbird before 16.0, Thunderbird ESR 10.x before 10.0.8, and SeaMonkey before 2.13 does not prevent access to properties of a prototype for a standard class, which allows remote attackers to execute arbitrary JavaScript code with chrome privileges via a crafted web site.
Conclusion & alert: CVE-2012-4184 is rated Moderate Risk (44.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.80%). 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 | 2026-06-15 | 1.10% | 1.80% | +0.70% |
| 2 | 2025-03-30 | 1.78% | 1.10% | -0.68% |
| 3 | 2025-03-29 | — | 1.78% | — |
Full EPSS history (7 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 4.3 | 2.0 | MEDIUM |
|
8.6 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
gentoo
|
high | CVE-2012-4184: 1 GLSA(s) (201301-01), 14 atom(s) (dev-libs/nss, mail-client/mozilla-thunderbird, …); latest impact high. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2012-4184 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2012-4184 |
suse
|
medium | CVE-2012-4184 severity moderate: SUSE including 67 source package names (MozillaFirefox, MozillaFirefox-10.0.9-0.3.1, …), 118 product×package rows across 43 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (43 product lines)): Fixed 87, Known Not Affected 31. | https://www.suse.com/security/cve/CVE-2012-4184/ |
ubuntu
|
medium | CVE-2012-4184 medium priority: Ubuntu including 4 source packages (firefox, seamonkey, thunderbird, xulrunner-1.9.2), 36 status rows across 9 suites (hardy, lucid, natty, oneiric, precise, quantal, raring, saucy, upstream): released 17, DNE 9, ignored 9, needs-triage 1. | https://ubuntu.com/security/CVE-2012-4184 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mozilla | firefox | < 10.0.8 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* |
| mozilla | thunderbird_esr | < 10.0.8 | cpe:2.3:a:mozilla:thunderbird_esr:*:*:*:*:*:*:*:* |
| mozilla | firefox | < 16.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* |
| mozilla | thunderbird | < 16.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| mozilla | seamonkey | < 2.13 | cpe:2.3:a:mozilla:seamonkey:*:*:*:*:*:*:*:* |
| canonical | ubuntu_linux | 10.04 | cpe:2.3:o:canonical:ubuntu_linux:10.04:*:*:*:-:*:*:* |
| canonical | ubuntu_linux | 11.04 | cpe:2.3:o:canonical:ubuntu_linux:11.04:*:*:*:*:*:*:* |
| canonical | ubuntu_linux | 11.10 | cpe:2.3:o:canonical:ubuntu_linux:11.10:*:*:*:*:*:*:* |
| canonical | ubuntu_linux | 12.04 | cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:esm:*:*:* |
| redhat | enterprise_linux_desktop | 5.0 | cpe:2.3:o:redhat:enterprise_linux_desktop:5.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_desktop | 6.0 | cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_eus | 6.3 | cpe:2.3:o:redhat:enterprise_linux_eus:6.3:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server | 5.0 | cpe:2.3:o:redhat:enterprise_linux_server:5.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server | 6.0 | cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_workstation | 5.0 | cpe:2.3:o:redhat:enterprise_linux_workstation:5.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_workstation | 6.0 | cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:* |
| suse | linux_enterprise_desktop | 10 | cpe:2.3:o:suse:linux_enterprise_desktop:10:sp4:*:*:*:*:*:* |
| suse | linux_enterprise_desktop | 11 | cpe:2.3:o:suse:linux_enterprise_desktop:11:sp3:*:*:*:*:*:* |
| suse | linux_enterprise_sdk | 10 | cpe:2.3:o:suse:linux_enterprise_sdk:10:sp4:*:*:*:*:*:* |
| suse | linux_enterprise_server | 10 | cpe:2.3:o:suse:linux_enterprise_server:10:sp4:*:*:*:*:*:* |
| suse | linux_enterprise_server | 11 | cpe:2.3:o:suse:linux_enterprise_server:11:sp3:*:*:*:*:*:* |
| suse | linux_enterprise_server | 11 | cpe:2.3:o:suse:linux_enterprise_server:11:sp3:*:*:*:vmware:*:* |