CVE-2026-84119CWE-416

CVE-2026-84119

Critical · published September 1, 2026

CVSS v3.1
9.6
EPSS
0%
Percentile
23.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.6 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00319 · 23.7th percentile
Weakness
CWE-416 · Use After Free
Published
2026-09-01T17:20Z
Affected products (7)
ProductVersionsFixed in
mozilla/firefox< 115.40.0115.40.0
mozilla/firefox≥ 116.0, < 140.15.0140.15.0
mozilla/firefox≥ 141.0.0, < 153.2.0153.2.0
mozilla/firefox≥ 154.0.0, < 155.0.0155.0.0
mozilla/thunderbird< 140.15.0140.15.0
mozilla/thunderbird≥ 141.0, < 153.2.0153.2.0
mozilla/thunderbird≥ 154.0, < 155.0155.0
References (8)
https://www.mozilla.org/security/advisories/mfsa2026-87/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-88/ · [email protected]https://bugzilla.mozilla.org/show_bug.cgi?id=2057817 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-82/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-83/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-84/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-85/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-86/ · [email protected]
EPSS history
Timeline
  • 03 SEP 03:32Z
    EPSS moved — → 0%
    epss
  • 01 SEP 12:18Z
    Sandbox escape due to use-after-free in the DOM: Navigation component
    cvelistv5