Description
Searching for a single word from the address bar caused an mDNS request to be sent on the local network searching for a hostname consisting of that string; resulting in an information leak. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | < 83 | — |
| Mozilla | Firefox ESR | < 78.5 | — |
| Mozilla | Thunderbird | < 78.5 | — |
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 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | MozillaFirefox | 78.5.0-8.17.1 | SUSE-SU-2020:3458-1 |
| SLES 15 SP2 | MozillaThunderbird | 78.5.0-3.107.1 | SUSE-SU-2020:3528-1 |
| SLES 15 SP1 | MozillaFirefox | 78.5.0-3.119.1 | SUSE-SU-2020:3383-1 |
| SLES 15 SP1 | MozillaThunderbird | 78.5.0-3.107.1 | SUSE-SU-2020:3528-1 |
| SLES 12 SP5 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SLES 12 SP4 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SLES 12 SP3 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SLES 11 SP4 | MozillaFirefox | 78.5.0-78.105.1 | SUSE-SU-2020:14548-1 |
| SLES for SAP 12 SP5 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SLES for SAP 12 SP4 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SLES for SAP 12 SP3 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SLES for SAP 12 SP2 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE OpenStack Cloud Crowbar 9 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE OpenStack Cloud Crowbar 8 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE OpenStack Cloud 9 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE OpenStack Cloud 8 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE OpenStack Cloud 7 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE HPE Helion OpenStack 8 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
| SUSE Enterprise Storage 5 | MozillaFirefox | 78.5.0-112.36.1 | SUSE-SU-2020:3548-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 92.0-1.2 | openSUSE-SU-2024:10600-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 91.1.1-1.1 | openSUSE-SU-2024:10601-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
| openSUSE Leap 15.2 | MozillaFirefox | 78.5.0-lp152.2.30.1 | openSUSE-SU-2020:2315-1, openSUSE-SU-2020:2020-1 |
| openSUSE Leap 15.2 | MozillaThunderbird | 78.5.0-lp152.2.19.1 | openSUSE-SU-2020:2096-1 |
| openSUSE Leap 15.1 | MozillaFirefox | 78.5.0-lp151.2.79.1 | openSUSE-SU-2020:2031-1 |
| openSUSE Leap 15.1 | MozillaThunderbird | 78.5.0-lp151.2.59.1 | openSUSE-SU-2020:2187-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 83.0-r0 | — |
| Alpine v3.23 | firefox +1 | 83.0-r0 | — |
| Alpine v3.23 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.23 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.22 | firefox +1 | 83.0-r0 | — |
| Alpine v3.22 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.22 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.21 | firefox +1 | 83.0-r0 | — |
| Alpine v3.21 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.21 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.20 | firefox | 83.0-r0 | — |
| Alpine v3.20 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.20 | thunderbird | 78.5.1-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 83.0-r0 | — |
| Alpine v3.19 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.19 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.18 | firefox | 83.0-r0 | — |
| Alpine v3.18 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.18 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.17 | firefox | 83.0-r0 | — |
| Alpine v3.17 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.17 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.16 | firefox | 83.0-r0 | — |
| Alpine v3.16 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.16 | thunderbird | 78.5.1-r0 | — |
| Alpine v3.15 | firefox | 83.0-r0 | — |
| Alpine v3.15 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.14 | firefox | 83.0-r0 | — |
| Alpine v3.14 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.13 | firefox | 83.0-r0 | — |
| Alpine v3.13 | firefox-esr | 78.5.0-r0 | — |
| Alpine v3.12 | firefox | 83.0-r0 | — |
| Alpine v3.12 | firefox-esr | 78.5.0-r0 | — |
Advisories 14
- WID-SEC-2026-0337 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 8, 2026
- openSUSE-SU-2020:2096-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14548-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:2315-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3528-1 Security update for MozillaThunderbird 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-2020:2031-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:2020-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3458-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:2187-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3548-1 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-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- SUSE-SU-2020:3383-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · May 2, 2025