# CVE-2026-54784

## Summary

- **CVE ID:** CVE-2026-54784
- **Severity:** HIGH
- **CVSS Score:** 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
- **CWE:** CWE-311, CWE-523
- **Published:** Jul 8, 2026
- **Last Modified:** Jul 10, 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.

## Affected Products

- CoreWCF — CoreWCF (>= 1.9.0, < 1.9.1)

## References

- [CNA](https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-2288-8h3r-cqgg)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/2afae08b2fa5288428df89e8161116b816cf6b4b)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/f216aa6929d41dc99cee098b1e69c260ec4c41c7)
- [CNA](https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 19.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._