CVE-2026-2748
Received Received - Intake
S/MIME Certificate Validation Flaw in SEPPmail Enables Spoofing

Publication date: 2026-03-04

Last updated on: 2026-03-05

Assigner: Switzerland Government Common Vulnerability Program

Description
SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.
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Meta Information
Published
2026-03-04
Last Modified
2026-03-05
Generated
2026-06-16
AI Q&A
2026-03-04
EPSS Evaluated
2026-06-15
NVD
CVE-2026-2748
EUVD
EUVD-2026-9385
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
seppmail seppmail to 15.0.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-295 The product does not validate, or incorrectly validates, a certificate.
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Executive Summary

This vulnerability affects SEPPmail Secure Email Gateway versions before 15.0.1. It occurs because the software improperly validates S/MIME certificates when the email addresses in those certificates contain whitespaces. This improper validation allows an attacker to spoof email signatures.

Impact Analysis

The vulnerability can allow attackers to spoof email signatures, potentially making malicious emails appear as if they come from trusted sources. This can lead to phishing attacks, unauthorized actions, or the spread of malware, undermining the trustworthiness of email communications.

Compliance Impact

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Detection Guidance

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