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Vulnerability · Published Jun 16, 2026 · Assigned by mozilla

CVE-2026-12328Memory safety bugs fixed in Firefox ESR 115.37, Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152

High 8.1

In plain English

A high-severity buffer overflow 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)8.1High
Exploit odds (30 days)0.5%top 58.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. 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 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10firefox140.12.0-1.el10_2ALSA-2026:27733
AlmaLinux:8firefox140.12.0-1.el8_10.alma.1ALSA-2026:27717
AlmaLinux:9firefox140.12.0-1.el9_8.alma.1ALSA-2026:27734
AlmaLinux:9firefox-x11140.12.0-1.el9_8.alma.1ALSA-2026:27734
AlmaLinux:10thunderbird140.12.0-1.el10_2.alma.1ALSA-2026:30846
AlmaLinux:8thunderbird140.12.0-1.el8_10.alma.1ALSA-2026:33445
AlmaLinux:9thunderbird140.12.0-1.el9_8.alma.1ALSA-2026:29940
Debian:12firefox-esr140.12.0esr-1~deb12u1DEBIAN-CVE-2026-12328
Debian:13firefox-esr140.12.0esr-1~deb13u1DEBIAN-CVE-2026-12328
Debian:14firefox-esr140.12.0esr-1DEBIAN-CVE-2026-12328
Debian:12thunderbird1:140.12.0esr-1~deb12u1DEBIAN-CVE-2026-12328
Debian:13thunderbird1:140.12.0esr-1~deb13u1DEBIAN-CVE-2026-12328
Debian:14thunderbird1:140.12.0esr-1DEBIAN-CVE-2026-12328
Rocky Linux:10firefox0:140.12.0-1.el10_2RLSA-2026:27733
Rocky Linux:8firefox0:140.12.0-1.el8_10RLSA-2026:27717
Rocky Linux:9firefox0:140.12.0-1.el9_8RLSA-2026:27734
Rocky Linux:10thunderbird0:140.12.0-1.el10_2RLSA-2026:30846
Rocky Linux:8thunderbird0:140.12.0-1.el8_10RLSA-2026:33445
Rocky Linux:9thunderbird0:140.12.0-1.el9_8RLSA-2026:29940
Ubuntu:22.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-12328
Ubuntu:24.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-12328
Ubuntu:24.04:LTSmozjs115no fix listedUBUNTU-CVE-2026-12328
Ubuntu:22.04:LTSmozjs78no fix listedUBUNTU-CVE-2026-12328
Ubuntu:22.04:LTSmozjs91no fix listedUBUNTU-CVE-2026-12328
Ubuntu:22.04:LTSthunderbirdno fix listedUBUNTU-CVE-2026-12328

Affected products (as reported)

VendorProductVersions
Mozilla Firefox see references
Mozilla Thunderbird see references

Weakness: CWE-120, CWE-825 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References