CVE-2026-29140 HIGH

CVE-2026-29140: S/MIME Signature Additional Certificate

Vendor Seppmail
Product Secure Email Gateway
Weakness CWE-295
Published April 2, 2026
Last update April 2, 2026
View on NVD All CVEs

CVSS base score

7.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

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

What the vulnerability does

01Description

SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to cause attacker-controlled certificates to be used for future encryption to a victim by adding the certificates to S/MIME signatures.

Key dates

02Disclosure timeline

April 2, 2026 CVE published
April 2, 2026 Record updated