CVE-2026-100804

Sandbox escape due to use-after-free in the Preferences: Backend component

Published Sep 29, 2026 CVSS 3.1 · 9.6 Critical EPSS < 1% KEV · Not listed
Description
Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Vendors & Products Mozilla thunderbird
Type Values Removed Values Added
Description Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Firefox 157. Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
References
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Weaknesses CWE-416
Metrics cvssV3_1

{'score': 9.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Firefox 157.
Title Sandbox escape due to use-after-free in the Preferences: Backend component
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Sep 30, 2026, 5:14 PM
Reserved
Sep 26, 2026, 7:17 PM
Status
Analyzed
Published
Sep 29, 2026, 1:17 PM
Modified
Oct 19, 2026, 5:38 PM
Severity
Moderate
Public date
Sep 29, 2026, 12:36 PM