VulnerabilityModified

CVE-2025-43921

GNU Mailman 2.1.39, as bundled in cPanel (and WHM), allows unauthenticated attackers to create lists via the /mailman/create endpoint.

MEDIUM 5.3EPSS 0.43%

Does this matter?

Lower severity and a low EPSS score (0.43%). Track it; it rarely justifies an emergency change on its own.

Description

GNU Mailman 2.1.39, as bundled in cPanel (and WHM), allows unauthenticated attackers to create lists via the /mailman/create endpoint. NOTE: multiple third parties report that they are unable to reproduce this, regardless of whether cPanel or WHM is used.

CVSS 3.1: 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.43% probability · 37th percentile
CISA KEV: Not listed
Weakness: CWE-863
Affected: gnu/mailman
Source: cve@mitre.org

References

https://code.launchpad.net/~mailman-coders/mailman/2.1Product
https://github.com/0NYX-MY7H/CVE-2025-43921Exploit, Third Party Advisory
https://github.com/cpanel/mailman2-python3
https://www.openwall.com/lists/oss-security/2025/04/21/6

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.