What’s Vulnerable › Vulnerabilities
CVE-2026-29140: S/MIME Signature Additional Certificate
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-02 · updated 2026-10-26
- Weakness: CWE-295
Description
SEPPmail Secure Email Gateway before version 15.0.3 allows an attacker to cause attacker-controlled certificates to be used for future encryption to a victim by adding the certificates to S/MIME signatures.
Affected products
- SEPPmail Secure Email Gateway: before 15.0.3 — fixed in 15.0.3
How to fix
Upgrade to a fixed version: SEPPmail Secure Email Gateway 15.0.3. Check the vendor advisory for mitigations.
References
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