CVE-2021-27180: An issue was discovered in MDaemon before 20.0.4

Q: How do I fix CVE-2021-27180?

mdaemon: upgrade to 20.0.4. Exact commands for each OS are on this page.

Q: Is CVE-2021-27180 being exploited?

CVE-2021-27180 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-27180 affect?

CVE-2021-27180 affects mdaemon. Severity is medium (CVSS 6.1). An issue was discovered in MDaemon before 20.0.4. There is Reflected XSS in Webmail (aka WorldClient). It can be exploited via a GET request. It allows performing any action with the privileges of the attacked user.

Q: How urgent is CVE-2021-27180?

Priority 41/100. Public exploit reference

This month

MEDIUM 6.1UPGRADE

CVE-2021-27180 is a medium-severity flaw (CVSS 6.1) affecting mdaemon. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in MDaemon before 20.0.4. There is Reflected XSS in Webmail (aka WorldClient). It can be exploited via a GET request. It allows performing any action with the privileges of the attacked user.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.9% (top 40%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-04-14
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: altn

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-04-14 23:15 UTCPublished CVE record published
2026-06-17 03:44 UTCUpdated Record last modified

altn mdaemon UPGRADE

Affected: < 20.0.4

Fixed in: 20.0.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy mdaemon || rpm -q mdaemon || mdaemon --version

2. UPGRADE to 20.0.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mdaemon

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mdaemon

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-27180?

mdaemon: upgrade to 20.0.4. Exact commands for each OS are on this page.

Is CVE-2021-27180 being exploited?

CVE-2021-27180 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-2021-27180 affect?

CVE-2021-27180 affects mdaemon. Severity is medium (CVSS 6.1). An issue was discovered in MDaemon before 20.0.4. There is Reflected XSS in Webmail (aka WorldClient). It can be exploited via a GET request. It allows performing any action with the privileges of the attacked user.

How urgent is CVE-2021-27180?

Priority 41/100. Public exploit reference

Related CVEs

CVE-2024-11182 MEDIUM 6.1 EXPLOITED UPGRADE MDaemon Email Server Cross-Site Scripting (XSS) Vulnerability
CVE-2022-29976 MEDIUM 5.4 UPGRADE An Authenticated Reflected Cross-site scripting at BCC Parameter was discovered in MDaemon before 22.0.0 .
CVE-2022-29975 MEDIUM 5.4 UPGRADE An Authenticated Reflected Cross-site scripting at CC Parameter was discovered in MDaemon before 22.0.0 .
CVE-2021-27183 HIGH 7.2 UPGRADE An issue was discovered in MDaemon before 20.0.4
CVE-2021-27182 HIGH 8.8 UPGRADE An issue was discovered in MDaemon before 20.0.4

References

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