CVE-2025-43920

low-risk

Published 2025-04-20

GNU Mailman 2.1.39, as bundled in cPanel (and WHM), in certain external archiver configurations, allows unauthenticated attackers to execute arbitrary OS commands via shell metacharacters in an email Subject line. NOTE: multiple third parties report that they are unable to reproduce this, regardless of whether cPanel or WHM is used.

Do I need to act?

1.4% chance of exploitation in next 30 days

EPSS score — moderate exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 5.4/10 Medium

NETWORK / HIGH complexity

Affected Products (1)

Mailman

Affected Vendors

Gnu

References (4)

Product https://code.launchpad.net/~mailman-coders/mailman/2.1

Exploit https://github.com/0NYX-MY7H/CVE-2025-43920

https://github.com/cpanel/mailman2-python3

https://www.openwall.com/lists/oss-security/2025/04/21/6

/ 100

low-risk

Severity 17/34 · Moderate

Exploitability 4/34 · Minimal

Exposure 5/34 · Minimal