CVE-2025-43921Public exploitNetwork attack vector

Unauthenticated list creation via missing CGI authorization

Published Apr 20, 2025 · Updated Apr 28, 2025

Incorrect authorization in GNU Mailman 2.1.39 bundled with cPanel and WHM allows remote attackers to create mailing lists. The reported create CGI accepts a POST to /mailman/create without enforcing the documented list-creator password, assigning the supplied owner to a new list. The claim requires the cPanel or WHM bundle, but cPanel and independent reviewers could not reproduce the behavior and cPanel disputes its validity.

CVSS severity5.3
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in GNU Mailman 2.1.39 bundled with cPanel and WHM allows remote attackers to create mailing lists. The reported create CGI accepts a POST to /mailman/create without enforcing the documented list-creator password, assigning the supplied owner to a new list. The claim requires the cPanel or WHM bundle, but cPanel and independent reviewers could not reproduce the behavior and cPanel disputes its validity.

The record

CVE
CVE-2025-43921
Published
Apr 20, 2025
Updated
Apr 28, 2025
Vendor
GNU Mailman
Product
Mailman
Classifications
CWE-863
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.1.39

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GNU Mailman · Mailmanversion=2.1.39

Published CVSS scores

5.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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