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8.2
SEPPmail Secure Email Gateway: Unsanitized S/MIME Header Injection
CVE-2026-27443
Summary
The SEPPmail Secure Email Gateway doesn't properly clean up email headers from encrypted messages. This can allow an attacker to manipulate trusted email headers, potentially leading to security issues. Update to version 15.0.1 or later to fix this issue.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| seppmail | seppmail | <= 15.0.1 | – |
Original title
SEPPmail Secure Email Gateway before version 15.0.1 does not properly sanitize the headers from S/MIME protected MIME entities, allowing an attacker to control trusted headers.
Original description
SEPPmail Secure Email Gateway before version 15.0.1 does not properly sanitize the headers from S/MIME protected MIME entities, allowing an attacker to control trusted headers.
nvd CVSS3.1
7.5
nvd CVSS4.0
8.2
Vulnerability type
CWE-20
Improper Input Validation
Published: 4 Mar 2026 · Updated: 13 Mar 2026 · First seen: 6 Mar 2026