CVE-2026-54784

EUVD-2026-42471
CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. In version 1.9.0, CoreWCF SPNEGO SecurityContextToken negotiation can expose the proof key recovered from the RSTR when TransportWithMessageCredential with Windows client credentials and session establishment are used, allowing an observer to impersonate the authenticated Windows principal and decrypt or forge WS-SecureConversation traffic. This issue is fixed in version 1.9.1.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.4 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 7%
Common Weakness Enumeration
References
https://github.com/CoreWCF/CoreWCF/commit/2afae08b2fa5288428df89e8161116b816cf6b4b
https://github.com/CoreWCF/CoreWCF/commit/f216aa6929d41dc99cee098b1e69c260ec4c41c7
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1
https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-2288-8h3r-cqgg