CVE-2026-4692
CRITICAL severity · CVSS 10
10CVSS CRITICAL
Summary
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.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)0%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Affected products we track (1)
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Additional information
- NVD record
- https://www.mozilla.org/security/advisories/mfsa2026-20/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-21/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-22/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-23/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-24/Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2017643