CVE-2016-5284

Name: CVE-2016-5284
Creator: NVD / NIST
Published: 2016-09-22T22:59:18.973+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 2.37%

Last modified Jun 17, 2026

CVE-2016-5284 is a vulnerability of currently unknown severity. 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.. EPSS estimates a 2.37% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability

2.37%

81.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	<= 48.0.2
Mozilla	Firefox	45.0
Mozilla	Firefox	45.0.1
Mozilla	Firefox	45.0.2
Mozilla	Firefox	45.1.1
Mozilla	Firefox	45.2.0
Mozilla	Firefox	45.3.0

References

http://rhn.redhat.com/errata/RHSA-2016-1912.html
http://seclists.org/dailydave/2016/q3/51Third Party Advisory
http://www.debian.org/security/2016/dsa-3674
http://www.mozilla.org/security/announce/2016/mfsa2016-85.htmlRelease Notes
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html
http://www.securityfocus.com/bid/93049
http://www.securitytracker.com/id/1036852
https://blog.mozilla.org/security/2016/09/16/update-on-add-on-pinning-vulnerability/Third Party Advisory, VDB Entry
https://bugzilla.mozilla.org/show_bug.cgi?id=1303127Issue Tracking, Third Party Advisory, VDB Entry
https://hackernoon.com/tor-browser-exposed-anti-privacy-implantation-at-mass-scale-bd68e9eb1e95Technical Description
https://security.gentoo.org/glsa/201701-15
https://www.mozilla.org/security/advisories/mfsa2016-86/
https://www.mozilla.org/security/advisories/mfsa2016-88/
http://rhn.redhat.com/errata/RHSA-2016-1912.html
http://seclists.org/dailydave/2016/q3/51Third Party Advisory
http://www.debian.org/security/2016/dsa-3674
http://www.mozilla.org/security/announce/2016/mfsa2016-85.htmlRelease Notes
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html
http://www.securityfocus.com/bid/93049
http://www.securitytracker.com/id/1036852
https://blog.mozilla.org/security/2016/09/16/update-on-add-on-pinning-vulnerability/Third Party Advisory, VDB Entry
https://bugzilla.mozilla.org/show_bug.cgi?id=1303127Issue Tracking, Third Party Advisory, VDB Entry
https://hackernoon.com/tor-browser-exposed-anti-privacy-implantation-at-mass-scale-bd68e9eb1e95Technical Description
https://security.gentoo.org/glsa/201701-15
https://www.mozilla.org/security/advisories/mfsa2016-86/
https://www.mozilla.org/security/advisories/mfsa2016-88/

Timeline

Published: Sep 22, 2016
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2016-5284?

How severe is CVE-2016-5284?

Severity scoring for CVE-2016-5284 is pending analysis. The EPSS model estimates a 2.37% probability of exploitation in the next 30 days.

How do I fix CVE-2016-5284?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2016-5284?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST