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Vulnerability · Published May 19, 2026 · Assigned by mozilla

CVE-2026-8975Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151

High 8.8

In plain English

A high-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 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.5%top 59.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Memory safety bugs present in Thunderbird 140.10 and Thunderbird 150. 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 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10firefox140.11.0-1.el10_2ALSA-2026:21380
AlmaLinux:8firefox140.11.0-1.el8_10.alma.1ALSA-2026:21382
AlmaLinux:9firefox140.11.0-1.el9_8.alma.1ALSA-2026:21378
AlmaLinux:9firefox-x11140.11.0-1.el9_8.alma.1ALSA-2026:21378
AlmaLinux:10thunderbird140.11.0-1.el10_2.alma.1ALSA-2026:22325
AlmaLinux:8thunderbird140.11.0-1.el8_10.alma.1ALSA-2026:22643
AlmaLinux:9thunderbird140.11.0-1.el9_8.alma.1ALSA-2026:21381
Debian:12firefox-esr140.11.0esr-1~deb12u1DEBIAN-CVE-2026-8975
Debian:13firefox-esr140.11.0esr-1~deb13u1DEBIAN-CVE-2026-8975
Debian:14firefox-esr140.11.0esr-1DEBIAN-CVE-2026-8975
Debian:12thunderbird1:140.11.0esr-1~deb12u1DEBIAN-CVE-2026-8975
Debian:13thunderbird1:140.11.0esr-1~deb13u1DEBIAN-CVE-2026-8975
Debian:14thunderbird1:140.11.0esr-1DEBIAN-CVE-2026-8975
Rocky Linux:10firefox0:140.11.0-1.el10_2RLSA-2026:21380
Rocky Linux:8firefox0:140.11.0-1.el8_10RLSA-2026:21382
Rocky Linux:9firefox0:140.11.0-1.el9_8RLSA-2026:21378
Rocky Linux:10thunderbird0:140.11.0-1.el10_2RLSA-2026:22325
Rocky Linux:8thunderbird0:140.11.0-1.el8_10RLSA-2026:22643
Rocky Linux:9thunderbird0:140.11.0-1.el9_8RLSA-2026:21381
Ubuntu:22.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-8975
Ubuntu:24.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-8975
Ubuntu:24.04:LTSmozjs115no fix listedUBUNTU-CVE-2026-8975
Ubuntu:22.04:LTSmozjs78no fix listedUBUNTU-CVE-2026-8975
Ubuntu:22.04:LTSmozjs91no fix listedUBUNTU-CVE-2026-8975
Ubuntu:22.04:LTSthunderbirdno fix listedUBUNTU-CVE-2026-8975

Affected products (as reported)

VendorProductVersions
Mozilla Firefox see references
Mozilla Thunderbird see references

Weakness: CWE-119, CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References