CVE-2026-84119

9.6 criticalEPSS 0.3%

Critical (9.6) in mozilla. EPSS 0.3% chance of exploitation in the next 30 days.

Sandbox escape due to use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Severity

CVSS 3.1

9.6 critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 24% of CVEs (scores of 2026-10-31)
CWE: CWE-416
Published: 2026-09-01
Modified: 2026-09-02
Record from: the NVD, synced 2026-10-19

Affected

mozilla:firefox
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2057817
https://www.mozilla.org/security/advisories/mfsa2026-82/
https://www.mozilla.org/security/advisories/mfsa2026-83/
https://www.mozilla.org/security/advisories/mfsa2026-84/
https://www.mozilla.org/security/advisories/mfsa2026-85/

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