XSS in Postfixadmin
CVE-2026-121551
PostfixAdmin through 4.0.5 contains a stored cross-site scripting vulnerability that allows authenticated mailbox users to inject script by creating a TOTP exception with an unescaped description. When a global administrator views totp-exceptions.php, the script runs in the admin session and can issue authenticated admin requests using the page's CSRF token.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
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
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/postfixadmin/postfixadmin/issues/1185 (issue-tracking)
- github.com/postfixadmin/postfixadmin (product)
- github.com/postfixadmin/postfixadmin/commit/0a894b08769481ce1a7f0f42af901c6d9f8… (patch)
- github.com/postfixadmin/postfixadmin/blob/v4.0.5/public/users/totp-exceptions.p… (technical-description)
- github.com/postfixadmin/postfixadmin/blob/v4.0.5/templates/totp-exceptions.tpl (technical-description)
- github.com/postfixadmin/postfixadmin/pull/1172 (issue-tracking, technical-description, patch)
- github.com/postfixadmin/postfixadmin/pull/1186 (issue-tracking, technical-description, patch)
- www.vulncheck.com/advisories/postfixadmin-through-4.0.5-stored-xss-via-totp-exc… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-121551?
- CVE-2026-121551 is a medium-severity vulnerability in Postfixadmin, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-11-03.
- How severe is CVE-2026-121551?
- Medium severity. CVSS v3 base score is 5.4 out of 10.