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dotnet · CoreWCF.PrimitivesCritical

CoreWCF.Primitives SAML Token Signature Verification Bypass

When a service validates SAML tokens using a non-X.

20 Jun 2026Read 1 minSeverity: act now

What changed

When a service validates SAML tokens using a non-X.509 method, the final signature verification is skipped.

Who it affects

Services using CoreWCF.Primitives that authenticate with SAML tokens via an out-of-band token resolver holding a non-X.509 SecurityToken (e.g., BinarySecretSecurityToken) referenced in the assertion's <KeyInfo>.

What to do today

Upgrade to CoreWCF v1.8.1 or v1.9.1 immediately.

The trail
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