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CVE-2026-54774highCWE-345CWE-347

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

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.4epss 0.1%
exploitation probability
0.1%top 95% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected products
CoreWCF · CoreWCF
References
https://github.com/CoreWCF/CoreWCF/commit/65d09022749854ba943e376aefb958dec05b00d8https://github.com/CoreWCF/CoreWCF/commit/b914495ce63c44924664643b60a262e7595081a4https://github.com/CoreWCF/CoreWCF/commit/e7454132876ecc7e2cf80e541a44376eeb54979bhttps://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-rpj7-hr7h-w6p9