Log in Start free

Vulnerability · Published Jan 13, 2026 · Assigned by mozilla

CVE-2026-0879Sandbox escape due to incorrect boundary conditions in the Graphics component

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 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.5%top 56.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10firefox140.7.0-1.el10_1ALSA-2026:2271
AlmaLinux:8firefox140.7.0-1.el8_10.alma.1ALSA-2026:0667
AlmaLinux:9firefox140.7.0-1.el9_7.alma.1ALSA-2026:0694
AlmaLinux:9firefox-x11140.7.0-1.el9_7.alma.1ALSA-2026:0694
AlmaLinux:10thunderbird140.7.0-1.el10_1.alma.1ALSA-2026:2286
AlmaLinux:8thunderbird140.7.0-1.el8_10.alma.1ALSA-2026:2220
AlmaLinux:9thunderbird140.7.0-1.el9_7.alma.1ALSA-2026:0924
Debian:12firefox-esr140.7.0esr-1~deb12u1DEBIAN-CVE-2026-0879
Debian:12firefox-esr140.7.0esr-1~deb12u1DSA-6101-1
Debian:13firefox-esr140.7.0esr-1~deb13u1DEBIAN-CVE-2026-0879
Debian:13firefox-esr140.7.0esr-1~deb13u1DSA-6101-1
Debian:14firefox-esr140.7.0esr-1DEBIAN-CVE-2026-0879
Debian:12thunderbird1:140.7.0esr-1~deb12u1DSA-6103-1
Debian:12thunderbird1:140.7.0esr-1~deb12u1DEBIAN-CVE-2026-0879
Debian:13thunderbird1:140.7.0esr-1~deb13u1DSA-6103-1
Debian:13thunderbird1:140.7.0esr-1~deb13u1DEBIAN-CVE-2026-0879
Debian:14thunderbird1:140.7.0esr-1DEBIAN-CVE-2026-0879
Rocky Linux:8firefox0:140.7.0-1.el8_10RLSA-2026:0667
Rocky Linux:9firefox0:140.7.0-1.el9_7RLSA-2026:0694
Rocky Linux:8thunderbird0:140.7.0-1.el8_10RLSA-2026:2220
Rocky Linux:9thunderbird0:140.7.0-1.el9_7RLSA-2026:0924
Ubuntu:22.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-0879
Ubuntu:24.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-0879
Ubuntu:24.04:LTSmozjs115no fix listedUBUNTU-CVE-2026-0879
Ubuntu:22.04:LTSmozjs78no fix listedUBUNTU-CVE-2026-0879
Ubuntu:22.04:LTSmozjs91no fix listedUBUNTU-CVE-2026-0879
Ubuntu:22.04:LTSthunderbird1:140.7.1+build1-0ubuntu0.22.04.1UBUNTU-CVE-2026-0879

Affected products (as reported)

VendorProductVersions
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

References