Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Firefox 157.
https://www.mozilla.org/security/advisories/mfsa2026-97/
https://bugzilla.mozilla.org/show_bug.cgi?id=2058647
Source: Mitre, NVD
Published: 2026-09-29
Updated: 2026-09-30
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Base Score: 9.6
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS: 0.0027