CVE-2026-29143 - Vulnerability Details - OpenCVE

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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact Low

Subsequent System Integrity Impact High

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Vendors	Products
Seppmail	Seppmail Secure Email Gateway

No data.

No data.

References

Link	Providers
https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure-1503

History

Thu, 02 Apr 2026 09:00:00 +0000

Type	Values Removed	Values Added
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.
Title		S/MIME Decryption Impersonation
First Time appeared		Seppmail Seppmail seppmail Secure Email Gateway
Weaknesses		CWE-20
CPEs		cpe:2.3:a:seppmail:seppmail_secure_email_gateway::::::::
Vendors & Products		Seppmail Seppmail seppmail Secure Email Gateway
References		https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure-1503
Metrics		cvssV4_0 `{'score': 7.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N'}`

MITRE

Status: PUBLISHED

Assigner: NCSC.ch

Published: 2026-04-02T08:49:31.012Z

Updated: 2026-04-02T08:49:31.012Z

Reserved: 2026-03-04T09:08:07.342Z

Link: CVE-2026-29143

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-04-02T09:16:23.123

Modified: 2026-04-02T09:16:23.123

Link: CVE-2026-29143

Redhat

No data.

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