CVE-2026-100811 Mozilla Firefox - Sandbox Escape

Mozilla Firefox < 157 and Firefox ESR < 153.4 contain a sandbox escape caused by use-after-free in the DOM: Core & HTML component, letting attackers escape sandbox restrictions, exploit requires crafted web content.

CVSS base score 9.6 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.26% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Sandbox Escape
Impact
Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Published
29 September 2026
Updated
15 October 2026
Weakness
CWE-416

Vendor fix

Update to Firefox ESR 153.4, Firefox 157, or later versions.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

← All CVEs