CVE-2016-5284

Severity: high (CVSS 7.4 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2016-09-22 · updated 2026-06-17
Weakness: CWE-20

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.

Affected products

Mozilla Firefox: through 48.0.2; 45.0, 45.0.1, 45.0.2, 45.1.1, 45.2.0, 45.3.0

References

http://rhn.redhat.com/errata/RHSA-2016-1912.html
http://seclists.org/dailydave/2016/q3/51
http://www.debian.org/security/2016/dsa-3674
http://www.mozilla.org/security/announce/2016/mfsa2016-85.html
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/
https://bugzilla.mozilla.org/show_bug.cgi?id=1303127
https://hackernoon.com/tor-browser-exposed-anti-privacy-implantation-at-mass-scale-bd68e9eb1e95
https://security.gentoo.org/glsa/201701-15
https://www.mozilla.org/security/advisories/mfsa2016-86/

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