What is CVE-2026-27443?

CVE-2026-27443 is a high-severity vulnerability in Seppmail Secure Email Gateway, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-03-04.

How severe is CVE-2026-27443?

High severity. CVSS v3 base score is 7.5 out of 10.

Improper input validation in Seppmail Secure Email Gateway

CVE-2026-27443

SEPPmail Secure Email Gateway before version 15.0.1 does not properly sanitize the headers from S/MIME protected MIME entities, allowing an attacker to control trusted headers.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.002 (12.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Seppmail Secure Email Gateway — versions 0
Seppmail

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

vulnerability@ncsc.ch (release-notes, Vendor Advisory)

Frequently asked questions

What is CVE-2026-27443?: CVE-2026-27443 is a high-severity vulnerability in Seppmail Secure Email Gateway, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-03-04.
How severe is CVE-2026-27443?: High severity. CVSS v3 base score is 7.5 out of 10.