Description
If a server sends two Strict-Transport-Security (STS) headers for a single connection, they will be rejected as invalid and HTTP Strict Transport Security (HSTS) will not be enabled for the connection. This vulnerability affects Firefox < 55.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | unspecified – < 55 | 55 |
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 16.04 LTS | firefox | 55.0.1+build2-0ubuntu0.16.04.2 | USN-3391-1 |
| Ubuntu 14.04 LTS | firefox | 55.0.1+build2-0ubuntu0.14.04.2 | USN-3391-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP5 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES 12 SP4 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES 12 SP3 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES 12 SP2 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES 12 SP1 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP5 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SLES for SAP 12 SP1 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
| SUSE Enterprise Storage 5 | MozillaFirefox | 68.2.0-109.95.2 | SUSE-SU-2019:2872-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 92.0-1.2 | openSUSE-SU-2024:10600-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
Advisories 5
- USN-3391-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- SUSE-SU-2019:2872-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10600-1 MozillaFirefox-92.0-1.2 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
- WID-SEC-2025-1211 Mozilla Firefox: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 2, 2025