Description
Memory safety bugs present in Firefox 120. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 121.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | unspecified – < 121 | 121 |
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.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 12 | thunderbird | 1:115.6.0-1~deb12u1 | DSA-5582-1 |
| Debian 11 | thunderbird | 1:115.6.0-1~deb11u1 | DSA-5582-1 |
| Debian 10 | thunderbird | 1:115.6.0-1~deb10u1 | DLA-3698-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | mozjs102 | No fix yet | — |
| Ubuntu 22.04 LTS | mozjs78 +2 | No fix yet | — |
| Ubuntu 20.04 LTS | firefox | 121.0+build1-0ubuntu0.20.04.1 | USN-6562-1 |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 121.0-1.1 | openSUSE-SU-2024:13531-1 |
| openSUSE Tumbleweed | firefox-esr | 128.5.1-1.1 | openSUSE-SU-2024:14572-1 |
Advisories 6
- USN-6562-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-5582-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3698-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:13531-1 MozillaFirefox-121.0-1.1 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
- WID-SEC-2023-3185 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 2, 2025