How severe is CVE-2011-2993?

CVE-2011-2993 has a CVSS 2.0 base score of 9.3, rated critical severity.

Is CVE-2011-2993 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-2993?

CVE-2011-2993 primarily affects Mozilla Firefox. In total, 37 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-2993?

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-2011-2993 published?

CVE-2011-2993 was published on 2011-08-18 and last updated on 2026-06-16.

CVE-2011-2993

CVE-2011-2993 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-264.

Key facts

Severity: Critical (CVSS 2.0 base score 9.3)
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Mozilla Firefox
Published: 2011-08-18
Last modified: 2026-06-16

Description

The implementation of digital signatures for JAR files in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, and possibly other products does not prevent calls from unsigned JavaScript code to signed code, which allows remote attackers to bypass the Same Origin Policy and gain privileges via a crafted web site, a different vulnerability than CVE-2008-2801.

Frequently asked questions

What is CVE-2011-2993?: The implementation of digital signatures for JAR files in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, and possibly other products does not prevent calls from unsigned JavaScript code to signed code, which allows remote attackers to bypass the Same Origin Policy and gain privileges via a crafted web site, a different vulnerability than CVE-2008-2801.
How severe is CVE-2011-2993?: CVE-2011-2993 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2011-2993 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-2993?: CVE-2011-2993 primarily affects Mozilla Firefox. In total, 37 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-2993?: 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-2011-2993 published?: CVE-2011-2993 was published on 2011-08-18 and last updated on 2026-06-16.

References

Affected products (37)

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:seamonkey:2.0:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:alpha_1:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:alpha_2:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:alpha_3:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:beta_1:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:beta_2:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:rc1:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0:rc2:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.3:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.4:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.5:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.6:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.7:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.8:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.9:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.10:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.0.11:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.1:alpha1:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.1:alpha2:*:*:*:*:*:*
cpe:2.3:a:mozilla:seamonkey:2.1:alpha3:*:*:*:*:*:*

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