CVE-2012-1947

CVE-2012-1947 is a critical-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 9.3. 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-119.

Key facts

• Severity: Critical (CVSS 2.0 base score 9.3)
• EPSS exploit prediction: 5% (91st percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-119
• Affected product: Mozilla Firefox
• Published: 2012-06-05
• Last modified: 2026-06-16

Description

Heap-based buffer overflow in the utf16_to_isolatin1 function in Mozilla Firefox 4.x through 12.0, Firefox ESR 10.x before 10.0.5, Thunderbird 5.0 through 12.0, Thunderbird ESR 10.x before 10.0.5, and SeaMonkey before 2.10 allows remote attackers to execute arbitrary code via vectors that trigger a character-set conversion failure.

Frequently asked questions

What is CVE-2012-1947?

Heap-based buffer overflow in the utf16_to_isolatin1 function in Mozilla Firefox 4.x through 12.0, Firefox ESR 10.x before 10.0.5, Thunderbird 5.0 through 12.0, Thunderbird ESR 10.x before 10.0.5, and SeaMonkey before 2.10 allows remote attackers to execute arbitrary code via vectors that trigger a character-set conversion failure.

How severe is CVE-2012-1947?

CVE-2012-1947 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2012-1947 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-1947?

CVE-2012-1947 primarily affects Mozilla Firefox. In total, 168 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-1947?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2012-1947 published?

CVE-2012-1947 was published on 2012-06-05 and last updated on 2026-06-16.

References

• http://lists.opensuse.org/opensuse-security-announce/2012-06/msg00012.html
• http://lists.opensuse.org/opensuse-security-announce/2012-06/msg00015.html
• http://rhn.redhat.com/errata/RHSA-2012-0710.html
• http://rhn.redhat.com/errata/RHSA-2012-0715.html
• http://www.debian.org/security/2012/dsa-2488
• http://www.debian.org/security/2012/dsa-2489
• http://www.mandriva.com/security/advisories?name=MDVSA-2012:088
• http://www.mozilla.org/security/announce/2012/mfsa2012-40.html
• https://bugzilla.mozilla.org/show_bug.cgi?id=744541
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16911

Affected products (168)

• cpe:2.3:a:mozilla:firefox:4.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta10:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta11:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta12:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta5:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta6:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta7:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta8:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0:beta9:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:4.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:5.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:5.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:6.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:6.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:6.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:7.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:8.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:8.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:9.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:9.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:10.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:11.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:12.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:firefox:12.0:beta6:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:*:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:1.0:alpha:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:1.0:beta:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:1.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:1.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:seamonkey:1.0.3:*:*:*:*:*:*:*

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