Description
A transient execution vulnerability, named Floating Point Value Injection (FPVI) allowed an attacker to leak arbitrary memory addresses and may have also enabled JIT type confusion attacks. (A related vulnerability, Speculative Code Store Bypass (SCSB), did not affect Firefox.). This vulnerability affects Firefox ESR < 78.9 and Firefox < 87.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox ESR | unspecified – < 78.9 | 78.9 |
| Mozilla | Firefox | unspecified – < 87 | 87 |
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 14 | firefox-esr | 78.9.0esr-1 | — |
| Debian 13 | firefox-esr | 78.9.0esr-1 | — |
| Debian 12 | firefox-esr | 78.9.0esr-1 | — |
| Debian 10 | firefox-esr | 78.9.0esr-1~deb10u1 | DSA-4874-1 |
| Debian 9 | firefox-esr | 78.9.0esr-1~deb9u1 | DLA-2607-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | mozjs78 | No fix yet | — |
| Ubuntu 20.04 LTS | mozjs52 +1 | No fix yet | — |
| Ubuntu 18.04 LTS | firefox | 87.0+build3-0ubuntu0.18.04.2 | — |
| Ubuntu 18.04 LTS | mozjs38 +1 | No fix yet | — |
Advisories 2
- DSA-4874-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2607-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026