Vulnerability · NVD
CVE-2026-4371
HIGH 7.4
A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in 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:H/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS
0.36%
exploit very unlikely
percentile 28.9%
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:*:*:*:*:-:*:*:* |