XSS in Webmin Usermin
CVE-2026-123622
Usermin through 2.570 contains a cross-site scripting vulnerability in mailbox/detach.cgi that allows remote attackers to execute script by supplying an arbitrary type parameter that bypasses JavaScript filtering. Attackers can email an HTML attachment containing script and lure recipients to a detach.cgi link with type=text/html to run script in the victim's authenticated Usermin session.
Vulnerability class: XSS (Cross-Site Scripting)
Published .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/webmin/usermin (product)
- github.com/webmin/usermin/blob/2.570/mailbox/detach.cgi (technical-description)
- github.com/webmin/usermin/commit/c5c43b9ad04a60809ac2eb271bf8f3d0fec2e46a (patch)
- github.com/webmin/usermin/issues/142 (issue-tracking)
- hackmd.io/@leediay/H144QKY6zl (technical-description)
- www.vulncheck.com/advisories/usermin-through-2.570-xss-via-mailbox-detach-cgi-t… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-123622?
- CVE-2026-123622 is a medium-severity vulnerability in Webmin Usermin, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-11-06.
- How severe is CVE-2026-123622?
- Medium severity. CVSS v3 base score is 6.1 out of 10.