CVE-2026-54774: Corewcf

High severity, CVSS 7.4. EPSS: 0.2% chance of exploitation in the next 30 days.

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, SamlSerializer skips final SignatureValue verification when a CoreWCF service validates SAML tokens using a non-X.509 signing token, allowing an attacker to reference a non-X.509 SecurityToken key identifier and bypass assertion signature verification. This issue is fixed in versions 1.8.1 and 1.9.1.

Affected products

• Corewcf Corewcf: from 1.9.0, before 1.9.1 (fixed in 1.9.1); before 1.8.1 (fixed in 1.8.1)

Published 2026-07-08. Last modified 2026-07-10.