Vulnerability · Published Jul 21, 2026 · Assigned by mozilla
CVE-2026-16361Memory safety bugs fixed in Thunderbird ESR 140.13
Critical 9.8
In plain English
A critical-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 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Memory safety bugs present in Thunderbird ESR 140.12. 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 was fixed in Firefox ESR 115.38, Firefox ESR 140.13, and Thunderbird 140.13.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | firefox | 140.13.0-1.el10_2 | ALSA-2026:47101 |
| AlmaLinux:8 | firefox | 140.13.0-1.el8_10.alma.1 | ALSA-2026:47105 |
| AlmaLinux:9 | firefox | 140.13.0-1.el9_8.alma.1 | ALSA-2026:47104 |
| AlmaLinux:9 | firefox-x11 | 140.13.0-1.el9_8.alma.1 | ALSA-2026:47104 |
| AlmaLinux:10 | thunderbird | 140.13.0-1.el10_2.alma.1 | ALSA-2026:49621 |
| AlmaLinux:8 | thunderbird | 140.13.0-1.el8_10.alma.1 | ALSA-2026:49922 |
| AlmaLinux:9 | thunderbird | 140.13.0-1.el9_8.alma.1 | ALSA-2026:49921 |
| Debian:12 | firefox-esr | 140.13.0esr-1~deb12u1 | DEBIAN-CVE-2026-16361 |
| Debian:13 | firefox-esr | 140.13.0esr-1~deb13u1 | DEBIAN-CVE-2026-16361 |
| Debian:14 | firefox-esr | 140.13.0esr-1 | DEBIAN-CVE-2026-16361 |
| Debian:12 | thunderbird | 1:140.13.0esr-2~deb12u1 | DEBIAN-CVE-2026-16361 |
| Debian:13 | thunderbird | 1:140.13.0esr-2~deb13u1 | DEBIAN-CVE-2026-16361 |
| Debian:14 | thunderbird | 1:140.13.0esr-1 | DEBIAN-CVE-2026-16361 |
| Rocky Linux:10 | firefox | 0:140.13.0-1.el10_2 | RLSA-2026:47101 |
| Rocky Linux:8 | firefox | 0:140.13.0-1.el8_10 | RLSA-2026:47105 |
| Rocky Linux:9 | firefox | 0:140.13.0-1.el9_8 | RLSA-2026:47104 |
| Rocky Linux:10 | thunderbird | 0:140.13.0-1.el10_2 | RLSA-2026:49621 |
| Rocky Linux:8 | thunderbird | 0:140.13.0-1.el8_10 | RLSA-2026:49922 |
| Rocky Linux:9 | thunderbird | 0:140.13.0-1.el9_8 | RLSA-2026:49921 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H