Description
Mozilla Firefox before 39.0, Firefox ESR 38.x before 38.1, and Thunderbird before 38.1 do not enforce key pinning upon encountering an X.509 certificate problem that generates a user dialog, which allows user-assisted man-in-the-middle attackers to bypass intended access restrictions by triggering a (1) expired certificate or (2) mismatched hostname for a domain with pinning enabled.
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.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | firefox | 39.0+build5-0ubuntu0.14.04.1 | USN-2656-1 |
| Ubuntu 14.04 LTS | thunderbird | 1:31.8.0+build1-0ubuntu0.14.04.1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | firefox | 38.1.0-1.el7_1 | RHSA-2015:1207 |
| RHEL 7 | thunderbird | 31.8.0-1.ael7b_1 | RHSA-2015:1455 |
| RHEL 6 | firefox | 38.1.0-1.el6_6 | RHSA-2015:1207 |
| RHEL 6 | thunderbird | 31.8.0-1.el6_6 | RHSA-2015:1455 |
| RHEL 5 | firefox | 38.1.0-1.el5_11 | RHSA-2015:1207 |
| RHEL 5 | thunderbird | 31.8.0-1.el5_11 | RHSA-2015:1455 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhel Productivity 5 | thunderbird | 31.8.0-1.el5_11 | RHSA-2015:1455 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 50.1.0-1.1 | openSUSE-SU-2024:10071-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 45.5.1-1.1 | openSUSE-SU-2024:10230-1 |
| 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 | 38.1.0-1.0.1.el7_1 | ELSA-2015-1207 |
| Oracle Linux 7 | thunderbird | 31.8.0-1.0.1.el7_1 | ELSA-2015-1455 |
Advisories 8
- RHSA-2015:1455 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2015:1207 Red Hat Security Advisory: firefox security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-2656-1 firefox vulnerabilities Ubuntu Security Notices (USN) · May 29, 2026
- openSUSE-SU-2024:10230-1 MozillaThunderbird-45.5.1-1.1 on GA media 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-2015-1455 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jul 20, 2015
- ELSA-2015-1207 Critical: firefox security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jul 3, 2015
References
- openSUSE-SU-2015:1229 vendor-advisory
- RHSA-2015:1455 vendor-advisory
- http://www.mozilla.org/security/announce/2015/mfsa2015-67.html
- GLSA-201512-10 vendor-advisory
- 75541 vdb-entry
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1147497
- 1032784 vdb-entry
- RHSA-2015:1207 vendor-advisory
- USN-2656-1 vendor-advisory
- 1032783 vdb-entry
- USN-2656-2 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html