CVE-2026-54784

CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality

State: Published
Severity: 7.4 High
Published: Jul 8, 2026
Updated: Jul 10, 2026
Reserved: Jun 15, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.4 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N	GitHub_M

Weaknesses

CWE-311 Missing Encryption of Sensitive Data
CWE-523 Unprotected Transport of Credentials

Affected Products

Product	Versions
CoreWCFCoreWCF	>= 1.9.0, < 1.9.1Affected

References

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