CVE-2026-54781

HIGH

CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced

Title source: cna
STIX 2.1

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 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.

References (6)

Core 6

Scores

CVSS v3 7.4
EPSS 0.0018
EPSS Percentile 7.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-287 CWE-345
Status published
Products (2)
CoreWCF/CoreWCF < 1.8.1
CoreWCF/CoreWCF >= 1.9.0, < 1.9.1
Published Jul 08, 2026
Tracked Since Jul 09, 2026