CVE-2026-100804
criticalSandbox escape due to use-after-free in the Preferences: Backend component.
Vendor / product: Mozilla — firefox
Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
CVSS
9.6
9.6 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
Timeline (UTC)
Published: 2026-09-29 13:17
Modified: 2026-10-19 17:38
NVD status: Analyzed
Last synced 2 days ago
Verified against the source API 2026-10-27 06:56 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
mozilla / firefox <157.0.0
mozilla / thunderbird <157.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://www.mozilla.org/security/advisories/mfsa2026-101/
Vendor advisory: https://www.mozilla.org/security/advisories/mfsa2026-97/
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2058647 security@mozilla.org
- https://www.mozilla.org/security/advisories/mfsa2026-101/ security@mozilla.org
- https://www.mozilla.org/security/advisories/mfsa2026-97/ security@mozilla.org
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:56 UTC · record ↗