CVE-2016-5284
Mozilla: Add-on update site certificate pin expiration (MFSA 2016-85, MFSA 2016-86)
Severity
ImportantRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · September 20, 2016
Updated · November 21, 2025
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 7.4CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
CVSS 2.0 · 5.1AV:N/AC:H/Au:N/C:P/I:P/A:P
CWE not specified