Vulnerability · Published Jun 16, 2026 · Assigned by mozilla
CVE-2026-12329Memory safety bug fixed in Thunderbird ESR 140.12
Medium 5.3
In plain English
A medium-severity memory corruption in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 75.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Memory safety bug fixed in Thunderbird ESR 140.12. This vulnerability was fixed in Firefox ESR 140.12 and Thunderbird 140.12.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | firefox | 140.12.0-1.el10_2 | ALSA-2026:27733 |
| AlmaLinux:8 | firefox | 140.12.0-1.el8_10.alma.1 | ALSA-2026:27717 |
| AlmaLinux:9 | firefox | 140.12.0-1.el9_8.alma.1 | ALSA-2026:27734 |
| AlmaLinux:9 | firefox-x11 | 140.12.0-1.el9_8.alma.1 | ALSA-2026:27734 |
| AlmaLinux:10 | thunderbird | 140.12.0-1.el10_2.alma.1 | ALSA-2026:30846 |
| AlmaLinux:8 | thunderbird | 140.12.0-1.el8_10.alma.1 | ALSA-2026:33445 |
| AlmaLinux:9 | thunderbird | 140.12.0-1.el9_8.alma.1 | ALSA-2026:29940 |
| Debian:12 | firefox-esr | 140.12.0esr-1~deb12u1 | DEBIAN-CVE-2026-12329 |
| Debian:13 | firefox-esr | 140.12.0esr-1~deb13u1 | DEBIAN-CVE-2026-12329 |
| Debian:14 | firefox-esr | 140.12.0esr-1 | DEBIAN-CVE-2026-12329 |
| Debian:12 | thunderbird | 1:140.12.0esr-1~deb12u1 | DEBIAN-CVE-2026-12329 |
| Debian:13 | thunderbird | 1:140.12.0esr-1~deb13u1 | DEBIAN-CVE-2026-12329 |
| Debian:14 | thunderbird | 1:140.12.0esr-1 | DEBIAN-CVE-2026-12329 |
| Rocky Linux:10 | firefox | 0:140.12.0-1.el10_2 | RLSA-2026:27733 |
| Rocky Linux:8 | firefox | 0:140.12.0-1.el8_10 | RLSA-2026:27717 |
| Rocky Linux:9 | firefox | 0:140.12.0-1.el9_8 | RLSA-2026:27734 |
| Rocky Linux:10 | thunderbird | 0:140.12.0-1.el10_2 | RLSA-2026:30846 |
| Rocky Linux:8 | thunderbird | 0:140.12.0-1.el8_10 | RLSA-2026:33445 |
| Rocky Linux:9 | thunderbird | 0:140.12.0-1.el9_8 | RLSA-2026:29940 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-12329 |
| Ubuntu:24.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-12329 |
| Ubuntu:25.10 | thunderbird | no fix listed | UBUNTU-CVE-2026-12329 |
| Ubuntu:26.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-12329 |
| Ubuntu:26.10 | thunderbird | no fix listed | UBUNTU-CVE-2026-12329 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-119, CWE-416, CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2044738
- https://www.mozilla.org/security/advisories/mfsa2026-58/
- https://www.mozilla.org/security/advisories/mfsa2026-61/
- https://access.redhat.com/security/cve/CVE-2026-12329 vdb-entry, x_refsource_REDHAT
- RHBZ#2489214 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12329.json x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:38506 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:36100 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:38751 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:27733 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:30846 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:27717 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:33445 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:36102 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:39428 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:37210 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:39141 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:36103 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:39142 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:36101 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:39706 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:39011 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:38753 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:37391 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:38750 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:27734 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:29940 vendor-advisory, x_refsource_REDHAT