CVE-2026-29137
Received Received - Intake
Subject Length Manipulation in SEPPmail Gateway Allows Security Tag Hiding

Publication date: 2026-04-02

Last updated on: 2026-04-16

Assigner: Switzerland Government Common Vulnerability Program

Description
SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to hide security tags from users by crafting a long subject.
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Meta Information
Published
2026-04-02
Last Modified
2026-04-16
Generated
2026-06-16
AI Q&A
2026-04-02
EPSS Evaluated
2026-06-15
NVD
CVE-2026-29137
EUVD
EUVD-2026-18154
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
seppmail secure_email_gateway to 15.0.3 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-20 The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
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Executive Summary

This vulnerability affects SEPPmail Secure Email Gateway versions before 15.0.3. It allows an attacker to hide security tags from users by crafting an email with a long subject line.

Impact Analysis

The vulnerability can impact users by preventing them from seeing important security tags in emails. This could lead to users missing warnings or indicators about the security status of an email, potentially increasing the risk of phishing or other email-based attacks.

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