{"id":"CVE-2026-100794","title":"Sandbox escape due to incorrect boundary conditions in the Internationalization component","summary":"Sandbox escape due to incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.","severity":"critical","cvss":9.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","cwe":["CWE-119"],"vendor":"Mozilla","product":"Thunderbird","affected":["Thunderbird","Firefox"],"published":"2026-09-29","updated":"2026-10-01","sourceUpdated":"2026-10-01T15:17:19.227","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100794","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2028871","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-100/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-101/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-102/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-103/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-97/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-99/","label":"security@mozilla.org"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100794.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-100794"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2543120"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-100794"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100794"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-102/#CVE-2026-100794"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-99/#CVE-2026-100794"},{"url":"https://access.redhat.com/errata/RHSA-2026:85240"},{"url":"https://access.redhat.com/errata/RHSA-2026:76764"},{"url":"https://access.redhat.com/errata/RHSA-2026:80674"},{"url":"https://access.redhat.com/errata/RHSA-2026:76850"},{"url":"https://access.redhat.com/errata/RHSA-2026:85243"},{"url":"https://access.redhat.com/errata/RHSA-2026:85242"},{"url":"https://access.redhat.com/errata/RHSA-2026:85241"},{"url":"https://access.redhat.com/errata/RHSA-2026:85244"},{"url":"https://access.redhat.com/errata/RHSA-2026:76761"},{"url":"https://access.redhat.com/errata/RHSA-2026:80694"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-01T14:55:02.726961Z"},"epss":0.00321,"epssPercentile":0.24943,"ingestedAt":"2026-09-29T13:34:31.667Z","scores":{"nvd":9.6,"vendor":6.1},"patched":["enterprise_linux_appstream_eus_v_10_0","enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_8","enterprise_linux_appstream_aus_v_8_4","enterprise_linux_appstream_eus_extension_v_8_4","enterprise_linux_appstream_e4s_v_9_2","enterprise_linux_appstream_e4s_v_9_4","enterprise_linux_appstream_eus_v_9_6","enterprise_linux_appstream_v_9"],"slug":"CVE-2026-100794","body":"## Overview\n\nSandbox escape due to incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100794.json)\n- **RHSA-2026:85240** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:85240)\n- **RHSA-2026:76764** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:76764)\n- **RHSA-2026:80674** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-10-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:80674)\n- **RHSA-2026:76850** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8) · released 2026-10-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:76850)\n- **RHSA-2026:85243** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:85243)\n- **RHSA-2026:85242** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2) · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:85242)\n- **RHSA-2026:85241** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4) · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:85241)\n- **RHSA-2026:85244** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6) · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:85244)\n- **RHSA-2026:76761** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:76761)\n- **RHSA-2026:80694** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-10-12 · [advisory](https://access.redhat.com/errata/RHSA-2026:80694)","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":52.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":214356,"id":"CVE-2026-100794","ts":1790869747107,"field":"cvss","old":null,"new":"9.6"},{"seq":214355,"id":"CVE-2026-100794","ts":1790869747107,"field":"severity","old":"none","new":"critical"}]}