Is CVE-2016-5284 in the CISA KEV catalog?

No. CVE-2016-5284 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2016-5284?

CVE-2016-5284 has a CVSS v3 base score of 7.4 (HIGH).

What is the EPSS score for CVE-2016-5284?

CVE-2016-5284 has an EPSS score of 2.37% (82th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2016-5284?

Upgrade firefox on debian unstable to 49.0-1 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2016-5284

HIGHEPSS 82th pctl

7.4

CVSS v3

NVD

Description

Mozilla Firefox before 49.0, Firefox ESR 45.x before 45.4, and Thunderbird < 45.4 rely on unintended expiration dates for Preloaded Public Key Pinning, which allows man-in-the-middle attackers to spoof add-on updates by leveraging possession of an X.509 server certificate for addons.mozilla.org signed by an arbitrary built-in Certification Authority.

CWE-20Improper Input Validation

How to fix

Remediation Available

firefoxDebian

Fixed in:49.0-1CVE-2016-5284

firefoxUbuntu

Fixed in:49.0+build4-0ubuntu0.14.04.1USN-3076-1

Fixed in:49.0+build4-0ubuntu0.16.04.1USN-3076-1

thunderbirdUbuntu

Fixed in:1:45.4.0+build1-0ubuntu0.14.04.1USN-3112-1

Fixed in:1:45.4.0+build1-0ubuntu0.16.04.1USN-3112-1

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

ScopeChanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

2.37%probability of exploitation in 30 days

82ndpercentile

Elevated risk: more likely to be exploited than 82% of all known CVEs.

References

Third-Party Advisory3

Release Notes1

mozilla.org

Technical Description1

hackernoon.com

Other references8

Related Vulnerabilities

Other CWE-20 (Improper Input Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-3400	Critical	10.0	100%	KEV + Ransom	-
CVE-2021-45105	Medium	5.9	100%	-	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-21985	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2018-7600	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-3452	High	7.5	100%	KEV	Fix

Embed a live status badge for CVE-2016-5284

Markdown

[![CVE-2016-5284](https://tridentstack.com/cve/badge/CVE-2016-5284.svg)](https://tridentstack.com/cve/CVE-2016-5284)

HTML

<a href="https://tridentstack.com/cve/CVE-2016-5284"><img src="https://tridentstack.com/cve/badge/CVE-2016-5284.svg" alt="CVE-2016-5284"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

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.