Vulnerability · NVD
CVE-2026-4721
CRITICAL 9.8
Memory safety bugs present in Firefox ESR 115.33, 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 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Attack vector : Network
No privileges required
No user interaction
Show raw CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.42%
exploit very unlikely
percentile 35.1%
Tracked apps referencing this CVE
For each app: the affected range, the fixing version, and where the tracked app stands today.
Vulnerable CPE configurations (2)
| Vendor | Product | Platform | Versions | CPE 2.3 URI |
|---|---|---|---|---|
| mozilla |
thunderbird All platforms (wildcard)
|
All platforms (wildcard) | <140.9.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* |
| mozilla |
thunderbird All platforms (wildcard)
|
All platforms (wildcard) | <149.0 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:* |