Is CVE-2012-4191 in the CISA KEV catalog?

No. CVE-2012-4191 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2012-4191?

CVE-2012-4191 has a CVSS v2 base score of 9.3 (HIGH).

What is the EPSS score for CVE-2012-4191?

CVE-2012-4191 has an EPSS score of 3.87% (89th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2012-4191?

Upgrade DeveloperEdition to 16.0.1 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2012-4191

HIGHEPSS 89th pctl

9.3

CVSS v2

NVD

Description

The mozilla::net::FailDelayManager::Lookup function in the WebSockets implementation in Mozilla Firefox before 16.0.1, Thunderbird before 16.0.1, and SeaMonkey before 2.13.1 allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors.

CWE-787Out-of-bounds Write

How to fix

Remediation Available

DeveloperEditionWindows application

Affected:16.0.1Fixed in:16.0.1Mozilla

Mozilla Firefox (en-US)Windows application

Affected:16.0.1Fixed in:16.0.1Mozilla

Mozilla Thunderbird (en-US)Windows application

Affected:16.0.1Fixed in:16.0.1Mozilla

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

3.87%probability of exploitation in 30 days

89thpercentile

Elevated risk: more likely to be exploited than 89% of all known CVEs.

References

Patch1

bugzilla.mozilla.org

Vendor Advisory1

mozilla.org

Third-Party Advisory8

Other references1

osvdb.org

Related Vulnerabilities

Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2023-4863	High	8.8	100%	KEV	Fix
CVE-2020-16040	Medium	6.5	100%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.