CVE-2026-54782

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

Published Jul 8, 2026 CVSS 3.1 · 10 Critical EPSS < 1% KEV · Not listed
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, 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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xjr9-gg9q-jx3v CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Corewcf
Corewcf corewcf
Vendors & Products Corewcf
Corewcf corewcf
Type Values Removed Values Added
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, 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.
Title CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation
Weaknesses CWE-290
CWE-347
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 10, 2026, 3:55 AM
Reserved
Jun 15, 2026, 11:23 PM
Status
Deferred
Published
Jul 8, 2026, 11:16 PM
Modified
Jul 10, 2026, 5:16 AM