CVE-2026-54782

CRITICAL 10.0

CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation

CVSS Score

10.0

EPSS Score

0.2%

EPSS Percentile

16th

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, CoreWCF SAML 1.1 and SAML 2.0 token validation does not correctly resolve the issuer signing key or require signed tokens when IdentityConfiguration is used with federated bindings, allowing an unauthenticated remote attacker to impersonate any principal the trusted STS could issue. This issue is fixed in versions 1.8.1 and 1.9.1.

CWE	CWE-290 CWE-347
Vendor	corewcf
Product	corewcf
Published	Jul 8, 2026
Last Updated	Jul 10, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

CoreWCF / CoreWCF

>= 1.9.0, < 1.9.1 < 1.8.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-xjr9-gg9q-jx3v github.com: https://github.com/CoreWCF/CoreWCF/commit/0b8c8af851260e85e8402af53233d1b8f87dfb6f github.com: https://github.com/CoreWCF/CoreWCF/commit/0e63c2cca55763d8be6b226a234579280a09e7b6 github.com: https://github.com/CoreWCF/CoreWCF/commit/e5cc9b6a4ecc102a50d782093bfc72e0790abe3d github.com: https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1 github.com: https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1