CVE-2026-29140

MEDIUM

S/MIME Signature Additional Certificate

Title source: cna
STIX 2.1

Description

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.

Scores

CVSS v3 5.3
EPSS 0.0002
EPSS Percentile 5.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-295
Status published
Products (2)
SEPPmail/Secure Email Gateway < 15.0.3
seppmail/secure_email_gateway < 15.0.3
Published Apr 02, 2026
Tracked Since Apr 02, 2026