CoreWCF up to 1.9.0 SPNEGO SecurityContextToken Negotiation improper authentication

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.0$0-$5k0.00

Summaryinfo

A vulnerability has been found in CoreWCF up to 1.9.0 and classified as critical. This affects an unknown part of the component SPNEGO SecurityContextToken Negotiation. The manipulation leads to improper authentication. This vulnerability is listed as CVE-2026-54784. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, has been found in CoreWCF up to 1.9.0. This issue affects an unknown part of the component SPNEGO SecurityContextToken Negotiation. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-54784 since 06/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. Neither technical details nor an exploit are publicly available.

Upgrading to version 1.9.1 eliminates this vulnerability.

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Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: CoreWCF 1.9.1

Timelineinfo

06/16/2026 CVE reserved
07/09/2026 +23 days Advisory disclosed
07/09/2026 +0 days VulDB entry created
07/09/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-54784 (🔒)
GCVE (CVE): GCVE-0-2026-54784
GCVE (VulDB): GCVE-100-377093

Entryinfo

Created: 07/09/2026 02:14
Changes: 07/09/2026 02:14 (52)
Complete: 🔍
Cache ID: 216::103

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