Description
If a valid external protocol handler was referenced in an image tag, the resulting broken image size could be distinguished from a broken image size of a non-existent protocol handler. This allowed an attacker to successfully probe whether an external protocol handler was registered. This vulnerability affects Firefox < 82.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | unspecified – < 82 | 82 |
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 | firefox | 82.0+build2-0ubuntu0.20.04.1 | USN-4599-1 |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | firefox | 82.0+build2-0ubuntu0.18.04.1 | USN-4599-1 |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
| Ubuntu 16.04 LTS | firefox | 82.0+build2-0ubuntu0.16.04.5 | USN-4599-2 |
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 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | librewolf | 82.0-r0 | — |
| Alpine v3.23 | firefox +1 | 82.0-r0 | — |
| Alpine v3.22 | firefox +1 | 82.0-r0 | — |
| Alpine v3.21 | firefox +1 | 82.0-r0 | — |
| Alpine v3.20 | firefox | 82.0-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | firefox | 82.0-r0 | — |
| Alpine v3.18 | firefox | 82.0-r0 | — |
| Alpine v3.17 | firefox | 82.0-r0 | — |
| Alpine v3.16 | firefox | 82.0-r0 | — |
| Alpine v3.15 | firefox | 82.0-r0 | — |
| Alpine v3.14 | firefox | 82.0-r0 | — |
| Alpine v3.13 | firefox | 82.0-r0 | — |
| Alpine v3.12 | firefox | 82.0-r0 | — |
Advisories 4
- USN-4599-2 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-4599-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 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