What is CVE-2020-18723?

CVE-2020-18723 is a medium-severity vulnerability in Altn Mdaemon Webmail, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-03.

How severe is CVE-2020-18723?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Altn Mdaemon Webmail

CVE-2020-18723

Stored cross-site scripting (XSS) in file attachment field in MDaemon webmail 19.5.5 allows an attacker to execute code on the email recipient side while forwarding an email to perform potentially malicious activities.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-02-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.038 (89.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.038 · newest: 0.038 · change: 0.000

Affected products

Altn Mdaemon Webmail

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

kailashbohara.com.np/blog/2020/07/15/mdaemon-stored-xss (Exploit, Third Party Advisory)
www.altn.com/Support/SecurityUpdate/MD082520_MDaemon_EN/ (Vendor Advisory)
packetstormsecurity.com/files/161332/Alt-N-MDaemon-Webmail-20.0.0-Cross-Site-Sc… (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2020-18723?: CVE-2020-18723 is a medium-severity vulnerability in Altn Mdaemon Webmail, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-02-03.
How severe is CVE-2020-18723?: Medium severity. CVSS v3 base score is 5.4 out of 10.