How severe is CVE-2012-1939?

CVE-2012-1939 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2012-1939 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-1939?

CVE-2012-1939 primarily affects Mozilla Firefox. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-1939?

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-2012-1939 published?

CVE-2012-1939 was published on 2012-06-05 and last updated on 2026-06-16.

CVE-2012-1939

CVE-2012-1939 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: 3% (86th 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

jsinfer.cpp in Mozilla Firefox ESR 10.x before 10.0.5 and Thunderbird ESR 10.x before 10.0.5 does not properly determine data types, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via crafted JavaScript code.

Frequently asked questions

What is CVE-2012-1939?: jsinfer.cpp in Mozilla Firefox ESR 10.x before 10.0.5 and Thunderbird ESR 10.x before 10.0.5 does not properly determine data types, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via crafted JavaScript code.
How severe is CVE-2012-1939?: CVE-2012-1939 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2012-1939 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-1939?: CVE-2012-1939 primarily affects Mozilla Firefox. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-1939?: 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-2012-1939 published?: CVE-2012-1939 was published on 2012-06-05 and last updated on 2026-06-16.

References

Affected products (10)

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:thunderbird_esr:10.0:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird_esr:10.0.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird_esr:10.0.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird_esr:10.0.3:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird_esr:10.0.4:*:*:*:*:*:*:*

More vulnerabilities in Mozilla Firefox

CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4692 — Critical (CVSS 10.0): Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR…
CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…

All CVEs affecting Mozilla Firefox →

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
CVE-2025-1866 — Critical (CVSS 10.0): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in warmcat libwebsockets allows…
CVE-2022-27625 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →