CVE-2026-100818
CRITICALCVSS 9.6Description
Sandbox escape due to use-after-free in the Widget: Gtk 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.
Timeline
Published:September 29th, 2026 1:17 PM
Last modified:October 5th, 2026 4:59 PM
CVSS Scoring
CVSS v3: 9.6 (CRITICAL)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Affected Software
From NVD CPE configuration data
Vendors
mozilla
Products
firefoxthunderbird
Weaknesses (CWE)
References & Reports
Advisories, patches, and third-party reports
- https://bugzilla.mozilla.org/show_bug.cgi?id=2069399Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-100/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-101/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-102/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-103/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-97/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-99/Vendor Advisory
Source: NIST NVD · Data may lag official sources by up to one minute