by Kastro
Paper/Archive/CVE-2026-4711

CVE-2026-4711

Mozilla Firefox — Use-after-free in the Widget: Cocoa component

EPSS 0.4%CVSS 9.8
critical.is priorityof 100
37
CVSS 9.8 (ADP, NVD agree)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 35.6.356 × 207.1No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory140.9CNA
Thunderbirdsee advisory140.9CNA

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=2017002refmozilla.org/security/advisories/mfsa2026-20refmozilla.org/security/advisories/mfsa2026-22refmozilla.org/security/advisories/mfsa2026-23refmozilla.org/security/advisories/mfsa2026-24