HarborGuard / CVE
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CRITICALCVE-2026-4720Published Modified CNA mozilla

CVE-2026-4720: Memory safety bugs fixed in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149

Memory safety bugs present in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Metrics

CVSS v3.1
9.8
Severity
CRITICAL
Fixed in
140.9
Affected Products
2

Fix available

140.9149
Affected packages
  • Mozilla / Firefox
    Fixed in 140.9, 149
  • Mozilla / Thunderbird
    Fixed in 140.9, 149
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References