CVE-2001-0021: MailMan Webmail 3.0.25 and earlier allows remote attackers to execute arbitrary commands via shell metacharact

This week

HIGH 10.0DOWNGRADE

CVE-2001-0021 is a high-severity flaw (CVSS 10.0) affecting mailman webmail. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

MailMan Webmail 3.0.25 and earlier allows remote attackers to execute arbitrary commands via shell metacharacters in the alternate_template parameter.

Why this priority

Critical severity
EPSS top 4%: very likely to be exploited
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	13.5% (top 4%)
CISA exploited list	No
Published	2001-02-16
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: endymion

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2001-02-16 05:00 UTCPublished CVE record published
2026-06-16 21:53 UTCUpdated Record last modified

endymion mailman webmail DOWNGRADE

Affected: 3.0 · 3.0.1 · 3.0.10 · 3.0.11 · 3.0.12 · 3.0.13 · 3.0.14 · 3.0.15

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0

1. Check installed version

apt-cache policy mailman-webmail || rpm -q mailman-webmail || mailman-webmail --version

2. No fixed release: DOWNGRADE to a release before 3.0 (Debian / Ubuntu)

apt-cache madison mailman-webmail sudo apt install mailman-webmail=<VERSION_BEFORE_3.0> sudo apt-mark hold mailman-webmail

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mailman-webmail sudo dnf downgrade mailman-webmail-<VERSION_BEFORE_3.0> sudo dnf versionlock add mailman-webmail

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Endymion MailMan 3.0.x - Arbitrary Command Execution

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2001-0021?

mailman webmail: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2001-0021 being exploited?

CVE-2001-0021 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2001-0021 affect?

CVE-2001-0021 affects mailman webmail. Severity is high (CVSS 10.0). MailMan Webmail 3.0.25 and earlier allows remote attackers to execute arbitrary commands via shell metacharacters in the alternate_template parameter.

How urgent is CVE-2001-0021?

Priority 64/100. Critical severity; EPSS top 4%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2002-0417 MEDIUM 5.0 DOWNGRADE Directory traversal vulnerability in Endymion MailMan before 3.1 allows remote attackers to read arbitrary fil
CVE-1999-0850 LOW 3.6 DOWNGRADE The default permissions for Endymion MailMan allow local users to read email or modify files.

References

← Back to latest CVEs