CVE-2026-27443 HIGH

CVE-2026-27443: S/MIME Decryption Tag Sanitization Bypass

Vendor Seppmail
Product Secure Email Gateway
Weakness CWE-20 · Input validation
Published March 4, 2026
Last update March 4, 2026
View on NVD All CVEs

CVSS base score

8.2/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 4, 2026 CVE published
March 4, 2026 Record updated