CVE-2026-4692
Critical · CVSS 10.0Mozilla Firefox / Thunderbird — Sandbox escape
- CVSS
- 10.0
- nvd
- EPSS
- —
- KEV
- No
- Class
- other
- NVD-CWE-noinfo, CWE-653
Description
Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Search profile — drives PoC discovery
Symbols Responsive Design ModeRDMmfsa2026-20mfsa2026-21mfsa2026-22mfsa2026-23bug 2017643
Keywords CVE-2026-4692Firefox sandbox escapeResponsive Design Mode sandboxFirefox RDM exploitFirefox 149 sandbox bypassThunderbird 140.9 sandbox escapemfsa2026-20 PoCCWE-653 sandbox escape Firefox
Versions: Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, Thunderbird < 140.9
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2017643
- https://www.mozilla.org/security/advisories/mfsa2026-20/
- https://www.mozilla.org/security/advisories/mfsa2026-21/
- https://www.mozilla.org/security/advisories/mfsa2026-22/
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/
- https://access.redhat.com/errata/RHSA-2026:5930
- https://access.redhat.com/errata/RHSA-2026:5931
- https://access.redhat.com/errata/RHSA-2026:5932
- https://access.redhat.com/errata/RHSA-2026:6188
- https://access.redhat.com/errata/RHSA-2026:6342
- https://access.redhat.com/errata/RHSA-2026:6917
Status: enriched · ingested 2026-06-30T06:00:22.000Z · profiled 2026-07-01T12:30:14.000Z