PT-2026-29706 · Seppmail · Seppmail Secure Email Gateway

Andris Suter-Dörig + 2 · Published 2026-04-02 · Updated 2026-04-02 · CVE-2026-29143

Positive Technologies (AI Summary)

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Name of the Vulnerable Software and Affected Versions SEPPmail Secure Email Gateway versions prior to 15.0.3

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

Recommendations Update to version 15.0.3 or later.

Fix

RCE

Weakness Enumeration

CWE-20

Related Identifiers

CVE-2026-29143

Affected Products

Seppmail Secure Email Gateway

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-29143 · Security Note
• https://twitter.com/CVEnew/status/2039647688745238536 · Twitter Post
• https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure-1503 · Note