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)

Published 2026-03-04 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.004 (27.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001

Affected products

Seppmail Secure Email Gateway — versions 0
Seppmail

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

downloads.seppmail.com/extrelnotes/150/ERN15.0.html (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.