Is CVE-2015-4509 in the CISA KEV catalog?

No. CVE-2015-4509 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2015-4509?

CVE-2015-4509 has a CVSS v2 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2015-4509?

CVE-2015-4509 has an EPSS score of 6.08% (93th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2015-4509?

Upgrade firefox on ubuntu 14.04 to 41.0+build3-0ubuntu0.14.04.1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2015-4509

HIGHEPSS 93th pctl

7.5

CVSS v2

NVD

Description

Use-after-free vulnerability in the HTMLVideoElement interface in Mozilla Firefox before 41.0 and Firefox ESR 38.x before 38.3 allows remote attackers to execute arbitrary code via crafted JavaScript code that modifies the URI table of a media element, aka ZDI-CAN-3176.

How to fix

Remediation Available

firefoxUbuntu

Fixed in:41.0+build3-0ubuntu0.14.04.1USN-2743-1

thunderbirdUbuntu

Fixed in:1:38.3.0+build1-0ubuntu0.14.04.1USN-2754-1

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

6.08%probability of exploitation in 30 days

93rdpercentile

High risk: more likely to be exploited than 93% of all known CVEs.

References

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Markdown

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HTML

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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.