CVE-2026-84129
CRITICAL severity · CVSS 9.8 · CWE-346
9.8CVSS CRITICAL
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.
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:U/C:H/I:H/A:H
Affected products we track (2)
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/mfsa2026-82/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-85/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-86/Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-88/Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=2055028