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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | firefox-esr | 45.4.0esr-1 | — |
| Debian 13 | firefox-esr | 45.4.0esr-1 | — |
| Debian 12 | firefox-esr | 45.4.0esr-1 | — |
| Debian 8 | firefox-esr | 45.4.0esr-1~deb8u2 | DSA-3674-1 |
| Debian 7 | firefox-esr | 45.4.0esr-1~deb7u1 | DLA-636-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | firefox | 49.0+build4-0ubuntu0.16.04.1 | USN-3076-1 |
| Ubuntu 16.04 LTS | thunderbird | 1:45.4.0+build1-0ubuntu0.16.04.1 | USN-3112-1 |
| Ubuntu 14.04 LTS | firefox | 49.0+build4-0ubuntu0.14.04.1 | USN-3076-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:45.4.0+build1-0ubuntu0.14.04.1 | USN-3112-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | firefox | 45.4.0-1.el7_2 | RHSA-2016:1912 |
| RHEL 6 | firefox | 45.4.0-1.el6_8 | RHSA-2016:1912 |
| RHEL 5 | firefox | 45.4.0-1.el5_11 | RHSA-2016:1912 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | MozillaFirefox | 45.4.0esr-81.1 | SUSE-SU-2016:2434-1 |
| SLES 12 | MozillaFirefox | 45.4.0esr-81.1 | SUSE-SU-2016:2434-1 |
| SLES 11 SP4 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
| SLES 11 SP3 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
| SLES 11 SP2 | MozillaFirefox | 45.4.0esr-52.1 | SUSE-SU-2016:2431-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | MozillaFirefox | 45.4.0esr-81.1 | SUSE-SU-2016:2434-1 |
| SLES for SAP 12 | MozillaFirefox | 45.4.0esr-81.1 | SUSE-SU-2016:2434-1 |
| SLES for SAP 11 SP4 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
| SUSE OpenStack Cloud 5 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
| SUSE Manager Proxy 2.1 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
| SUSE Manager 2.1 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | MozillaFirefox | 45.4.0esr-53.1 | SUSE-SU-2016:2513-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 50.1.0-1.1 | openSUSE-SU-2024:10071-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | firefox | 45.4.0-1.0.1.el7_2 | ELSA-2016-1912 |
Advisories 11
- RHSA-2016:1912 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-3112-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3076-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-636-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3674-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:2513-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2434-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2431-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14572-1 firefox-esr-128.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10071-1 MozillaFirefox-50.1.0-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ELSA-2016-1912 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Sep 21, 2016
References
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html
- http://www.mozilla.org/security/announce/2016/mfsa2016-85.html
- https://www.mozilla.org/security/advisories/mfsa2016-86/
- https://blog.mozilla.org/security/2016/09/16/update-on-add-on-pinning-vulnerability/
- https://hackernoon.com/tor-browser-exposed-anti-privacy-implantation-at-mass-scale-bd68e9eb1e95
- DSA-3674 vendor-advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1303127
- [dailydave] 20160915 Deep down the certificate pinning rabbit hole of "Tor Browser Exposed" mailing-list
- GLSA-201701-15 vendor-advisory
- RHSA-2016:1912 vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2016-88/
- 93049 vdb-entry
- 1036852 vdb-entry