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CRITICAL · 9.1

CVE-2026-29143

SEPPmail Secure Email Gateway before version 15.0.3 does not properly authenticate the inner message of S/MIME-encrypted MIME entities, allowing an attacker to control trusted headers.

Vulnerability Description

SEPPmail Secure Email Gateway before version 15.0.3 does not properly authenticate the inner message of S/MIME-encrypted MIME entities, allowing an attacker to control trusted headers.

CVSS Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE

Affected Products

VendorProductVersions
SeppmailSecure Email Gateway< 15.0.3

Related Weaknesses (CWE)

CWE-20

References

FAQ

What is CVE-2026-29143?

CVE-2026-29143 is a vulnerability with a CVSS score of 9.1 (CRITICAL). SEPPmail Secure Email Gateway before version 15.0.3 does not properly authenticate the inner message of S/MIME-encrypted MIME entities, allowing an attacker to control trusted headers.

How severe is CVE-2026-29143?

CVE-2026-29143 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-29143?

Check the references section above for vendor advisories and patch information. Affected products include: Seppmail Secure Email Gateway.