CVE-2026-44126: Insecure deserialization

Severity: critical (CVSS 9.2 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-08 · updated 2026-10-26
Weakness: CWE-502

Description

SEPPmail Secure Email Gateway before version 15.0.4 insecurely deserializes untrusted data, which can be reached from the new GINA UI and may allow unauthenticated remote attackers to execute code via a crafted serialized object.

Affected products

SEPPmail AG Secure Email Gateway: before 15.0.4 — fixed in 15.0.4

How to fix

Upgrade to a fixed version: SEPPmail AG Secure Email Gateway 15.0.4. Check the vendor advisory for mitigations.

References

https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#security
https://labs.infoguard.ch/posts/seppmail_secure_e-mail_gateway_rce_vulnerabilities_cve-2026-2743_cve-2026-7864_cve-2026-44127_cve-2026-44128/

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