CVE-2026-54781
Published:July 08, 2026
Updated:July 21, 2026
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 token validation does not enforce SubjectConfirmation method URIs or holder-of-key proof keys in SamlSecurityTokenHandler, allowing holder-of-key downgrade or custom confirmation method assertions to authenticate a subject without proving authority over the assertion. This issue is fixed in versions 1.8.1 and 1.9.1.
Affected Packages
corewcf.primitives (DOT_NET):
Affected version(s) >=0.1.0.8 <1.8.1Fix Suggestion:
Update to version 1.8.1https://github.com/CoreWCF/CoreWCF.git (GITHUB):
Affected version(s) >=v0.3.0 <v1.8.1Fix Suggestion:
Update to version v1.8.1https://github.com/CoreWCF/CoreWCF.git (GITHUB):
Affected version(s) =v1.9.0 <v1.9.1Fix Suggestion:
Update to version v1.9.1corewcf.primitives (NUGET):
Affected version(s) =1.9.0 <1.9.1Fix Suggestion:
Update to version 1.9.1corewcf.primitives (NUGET):
Affected version(s) >=0.1.0-preview <1.8.1Fix Suggestion:
Update to version 1.8.1Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
9.1
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.4
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
EPSS
Base Score:
0.18