How severe is CVE-2012-3976?

CVE-2012-3976 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2012-3976 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-3976?

CVE-2012-3976 primarily affects Mozilla Firefox. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-3976?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2012-3976 published?

CVE-2012-3976 was published on 2012-08-29 and last updated on 2026-06-16.

CVE-2012-3976

CVE-2012-3976 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Mozilla Firefox
Published: 2012-08-29
Last modified: 2026-06-16

Description

Mozilla Firefox before 15.0, Firefox ESR 10.x before 10.0.7, and SeaMonkey before 2.12 do not properly handle onLocationChange events during navigation between different https sites, which allows remote attackers to spoof the X.509 certificate information in the address bar via a crafted web page.

Frequently asked questions

What is CVE-2012-3976?: Mozilla Firefox before 15.0, Firefox ESR 10.x before 10.0.7, and SeaMonkey before 2.12 do not properly handle onLocationChange events during navigation between different https sites, which allows remote attackers to spoof the X.509 certificate information in the address bar via a crafted web page.
How severe is CVE-2012-3976?: CVE-2012-3976 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2012-3976 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-3976?: CVE-2012-3976 primarily affects Mozilla Firefox. In total, 21 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-3976?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2012-3976 published?: CVE-2012-3976 was published on 2012-08-29 and last updated on 2026-06-16.

References

Affected products (21)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:*:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:12.2:*:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_desktop:10:sp4:*:*:-:*:*:*
cpe:2.3:o:suse:linux_enterprise_desktop:11:sp2:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:10:sp4:*:*:-:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:11:sp2:*:*:*:-:*:*
cpe:2.3:o:suse:linux_enterprise_server:11:sp2:*:*:*:vmware:*:*
cpe:2.3:o:suse:linux_enterprise_software_development_kit:11:sp2:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:5.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_eus:6.3:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:5.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_server_eus:6.3:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_workstation:5.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:10.04:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:11.04:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:11.10:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:esm:*:*:*

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