Description
A double-free issue could have occurred in `sec_pkcs7_decoder_start_decrypt()` when handling an error path. Under specific conditions, the same symmetric key could have been freed twice, potentially leading to memory corruption. This vulnerability affects Firefox < 133, Thunderbird < 133, Firefox ESR < 128.7, and Thunderbird < 128.7.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Firefox | unspecified – < 133 | 133 |
| Mozilla | Thunderbird | unspecified – < 133, unspecified – < 128.7 | 133 |
| Mozilla | Firefox ESR | unspecified – < 128.7 | 128.7 |
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 | 128.7.0esr-1 | — |
| Debian 14 | thunderbird | 1:128.7.0esr-1 | — |
| Debian 13 | firefox-esr | 128.7.0esr-1 | — |
| Debian 13 | thunderbird | 1:128.7.0esr-1 | — |
| Debian 12 | firefox-esr | 128.7.0esr-1~deb12u1 | DSA-5858-1 |
| Debian 12 | thunderbird | 1:128.7.0esr-1~deb12u1 | DSA-5861-1 |
| Debian 11 | firefox-esr | 128.7.0esr-1~deb11u1 | DLA-4044-1 |
| Debian 11 | thunderbird | 1:128.7.0esr-1~deb11u1 | DLA-4045-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | mozjs102 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | mozjs78 +2 | No fix yet | — |
| Ubuntu 20.04 LTS | firefox | 133.0+build2-0ubuntu0.20.04.1 | USN-7134-1 |
| 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 SP6 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLES 15 SP6 | MozillaThunderbird | 128.7.0-150200.8.200.1 | SUSE-SU-2025:0405-1 |
| SLES 15 SP5 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLES 15 SP4 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLES 15 SP3 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLES 12 SP5 | MozillaFirefox | 128.7.0-112.246.1 | SUSE-SU-2025:0391-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP5 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLES for SAP 15 SP4 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLES for SAP 15 SP3 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLE HPC 15 SP5 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLE HPC 15 SP4 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SLE HPC 15 SP3 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| SUSE Enterprise Storage 7.1 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaFirefox | 133.0.3-1.1 | openSUSE-SU-2024:14583-1 |
| openSUSE Tumbleweed | firefox-esr +1 | 128.7.0-1.1 | openSUSE-SU-2025:14731-1, openSUSE-SU-2025:14727-1 |
| openSUSE Leap 15.6 | MozillaFirefox | 128.7.0-150200.152.170.1 | SUSE-SU-2025:0374-1 |
| openSUSE Leap 15.6 | MozillaThunderbird | 128.7.0-150200.8.200.1 | SUSE-SU-2025:0405-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | firefox | 133.0-r0 | — |
Advisories 14
- WID-SEC-2024-3549 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · May 31, 2026
- USN-7134-1 firefox vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-5858-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-5861-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-4045-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-4044-1 firefox-esr - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2025:0405-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14583-1 MozillaFirefox-133.0.3-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2025:14731-1 MozillaThunderbird-128.7.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0374-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2025:14727-1 firefox-esr-128.7.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2025:0391-1 Security update for MozillaFirefox SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2025-0262 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 2, 2026
- NCSC-2025-0040 Kwetsbaarheden verholpen in Mozilla Firefox en Thunderbird NCSC-NL (Netherlands) · Feb 7, 2025