Is CVE-2015-2731 in the CISA KEV catalog?

No. CVE-2015-2731 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2015-2731?

CVE-2015-2731 has a CVSS v2 base score of 10.0 (HIGH).

What is the EPSS score for CVE-2015-2731?

CVE-2015-2731 has an EPSS score of 5.79% (92th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2015-2731?

Upgrade firefox on ubuntu 14.04 to 39.0+build5-0ubuntu0.14.04.1 or later.

CVE & CISA-KEV Catalog

CVE-2015-2731

HIGHEPSS 92th pctl

10.0

CVSS v2

NVD

Description

Use-after-free vulnerability in the CSPService::ShouldLoad function in the microtask implementation in Mozilla Firefox before 39.0, Firefox ESR 38.x before 38.1, and Thunderbird before 38.1 allows remote attackers to execute arbitrary code by leveraging client-side JavaScript that triggers removal of a DOM object on the basis of a Content Policy.

How to fix

Remediation Available

firefoxUbuntu

Fixed in:39.0+build5-0ubuntu0.14.04.1USN-2656-1

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

5.79%probability of exploitation in 30 days

92ndpercentile

High risk: more likely to be exploited than 92% of all known CVEs.

References

Vendor Advisory1

mozilla.org

Third-Party Advisory2

Issue Tracking1

bugzilla.mozilla.org

Other references10

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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 2026-05-06.