What’s Vulnerable › Vulnerabilities

CVE-2026-54774: CoreWCF: SamlSerializer skips SignatureValue verification when SAML signing token is not an X.509 certificate

• Severity: high (CVSS 7.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-08 · updated 2026-07-10
• Weakness: CWE-345

Description

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: from 1.9.0, < 1.9.1; before 1.8.1

References

• https://github.com/CoreWCF/CoreWCF/commit/65d09022749854ba943e376aefb958dec05b00d8
• https://github.com/CoreWCF/CoreWCF/commit/b914495ce63c44924664643b60a262e7595081a4
• https://github.com/CoreWCF/CoreWCF/commit/e7454132876ecc7e2cf80e541a44376eeb54979b
• https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1
• https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1
• https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-rpj7-hr7h-w6p9

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