What is CVE-2026-29136?

CVE-2026-29136 is a medium-severity vulnerability in Seppmail Secure Email Gateway, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-02.

How severe is CVE-2026-29136?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Seppmail Secure Email Gateway

CVE-2026-29136

SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to inject HTML into notification emails about new CA certificates.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.001 (1.0th percentile) — read the EPSS interpretation.

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.

Affected products

Seppmail Secure Email Gateway — versions 0
Seppmail Secure_email_gateway

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

vulnerability@ncsc.ch (release-notes, Release Notes)

Frequently asked questions

What is CVE-2026-29136?: CVE-2026-29136 is a medium-severity vulnerability in Seppmail Secure Email Gateway, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-02.
How severe is CVE-2026-29136?: Medium severity. CVSS v3 base score is 6.1 out of 10.