CVE-2026-84140
Critical
9.8 CVSS v3.1
- Published
- Sep 1, 2026
- Updated
- Sep 3, 2026
- Vendor
- Mozilla
- Affected versions
- See affected products
- Weakness
- CWE-346
Summary
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
Severity
Critical (9.8)CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
- Mozilla Firefox < 153.2.0
- Mozilla Firefox >= 154.0.0, < 155.0.0
- Mozilla Thunderbird < 153.2.0
- Mozilla Thunderbird >= 154.0, < 155.0
Exploitation status
Unknown
Technical details
Technical analysis has not been written for this record yet.
Mitigation & remediation
Follow the vendor advisory linked below for patches and workarounds.