CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality (CVE-2026-54784) | HOL Guard CVE

High · CVSS 7.4CVE-2026-54784GHSA-2288-8H3R-CQGG

CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality

Answer in brief

CVE-2026-54784 records a High severity (CVSS 7.4) vulnerability in CoreWCF: SPNEGO SecurityContextToken proof key wrapped without confidentiality. The current sources do not mark it as known exploited. The current feed maps CoreWCF/CoreWCF (generic), CoreWCF.Primitives (nuget). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 8, 2026Updated Jul 10, 2026Source checked Sep 17, 2026First seen by HOL Jun 19, 2026Material review Jul 10, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.4
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps CoreWCF/CoreWCF (generic), CoreWCF.Primitives (nuget). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
CoreWCF/CoreWCFgeneric	>= 1.9.0, < 1.9.1	Not reported
CoreWCF.Primitivesnuget	>=1.9.0,<1.9.1	1.9.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for CoreWCF/CoreWCF, CoreWCF.Primitives.
Review the reported fix. Update CoreWCF.Primitives to 1.9.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Jul 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 19, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.