CVE-2026-84124CWE-416

CVE-2026-84124

Medium · published September 1, 2026

CVSS v3.1
5.4
EPSS
0%
Percentile
6.1
In the wild
Unconfirmed
What it is

Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00170 · 6.1th percentile
Weakness
CWE-416 · Use After Free
Published
2026-09-01T17:20Z
Affected products (6)
ProductVersionsFixed in
mozilla/firefox< 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 (7)
https://bugzilla.mozilla.org/show_bug.cgi?id=2061110 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-82/ · [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]https://www.mozilla.org/security/advisories/mfsa2026-87/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-88/ · [email protected]
EPSS history
Timeline
  • 03 SEP 03:32Z
    EPSS moved — → 0%
    epss
  • 01 SEP 12:18Z
    Use-after-free in the DOM: Core & HTML component
    cvelistv5