Description
WebExtensions could use popups and panels in the extension UI to load an "about:" privileged URL, violating security checks that disallow this behavior. This vulnerability affects Firefox < 56.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | unspecified – < 56 | 56 |
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 18.04 LTS | firefox | 56.0+build6-0ubuntu1 | — |
| Ubuntu 16.04 LTS | firefox | 56.0+build6-0ubuntu0.16.04.1 | USN-3435-1 |
| Ubuntu 14.04 LTS | firefox | 56.0+build6-0ubuntu0.14.04.1 | USN-3435-1 |
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 3
- USN-3435-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 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