Is CVE-2016-5259 in the CISA KEV catalog?

No. CVE-2016-5259 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2016-5259?

CVE-2016-5259 has a CVSS v3 base score of 8.8 (HIGH).

What is the EPSS score for CVE-2016-5259?

CVE-2016-5259 has an EPSS score of 3.26% (87th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2016-5259?

Upgrade firefox on debian unstable to 48.0-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2016-5259

HIGHEPSS 87th pctl

8.8

CVSS v3

NVD

Description

Use-after-free vulnerability in the CanonicalizeXPCOMParticipant function in Mozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 allows remote attackers to execute arbitrary code via a script that closes its own Service Worker within a nested sync event loop.

CWE-416Use After Free

How to fix

Remediation Available

firefoxDebian

Fixed in:48.0-1CVE-2016-5259

firefoxUbuntu

Fixed in:48.0+build2-0ubuntu0.14.04.1USN-3044-1

Fixed in:48.0+build2-0ubuntu0.16.04.1USN-3044-1

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

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploit Intelligence

3.26%probability of exploitation in 30 days

87thpercentile

Elevated risk: more likely to be exploited than 87% of all known CVEs.

References

Exploit1

bugzilla.mozilla.org

Vendor Advisory1

mozilla.org

Third-Party Advisory1

oracle.com

Other references8

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2015-0313	Critical	9.8	96%	KEV	Fix
CVE-2017-9798	High	7.5	95%	-	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 2026-05-06.