CVE-2026-100819
CRITICAL
CVSS 9.6
Published: 2026-09-29
Modified: 2026-09-30
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Description
Sandbox escape due to incorrect boundary conditions in the XPCOM component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
Quick Facts
| CVE ID | CVE-2026-100819 |
| CVSS Score | 9.6 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H |
| Published | 2026-09-29 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2071069
- https://www.mozilla.org/security/advisories/mfsa2026-100/
- https://www.mozilla.org/security/advisories/mfsa2026-101/
- https://www.mozilla.org/security/advisories/mfsa2026-102/
- https://www.mozilla.org/security/advisories/mfsa2026-103/
- https://www.mozilla.org/security/advisories/mfsa2026-97/
- https://www.mozilla.org/security/advisories/mfsa2026-98/
- https://www.mozilla.org/security/advisories/mfsa2026-99/