High severity7.4NVD Advisory· Published Jul 8, 2026· Updated Jul 9, 2026
CVE-2026-54781
CVE-2026-54781
Description
CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF SAML token validation does not enforce SubjectConfirmation method URIs or holder-of-key proof keys in SamlSecurityTokenHandler, allowing holder-of-key downgrade or custom confirmation method assertions to authenticate a subject without proving authority over the assertion. This issue is fixed in versions 1.8.1 and 1.9.1.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
CoreWCF.PrimitivesNuGet | < 1.8.1 | 1.8.1 |
CoreWCF.PrimitivesNuGet | >= 1.9.0, < 1.9.1 | 1.9.1 |
Affected products
1Patches
Vulnerability mechanics
References
7- github.com/advisories/GHSA-48pq-2xq3-c2m4ghsaADVISORY
- github.com/CoreWCF/CoreWCF/security/advisories/GHSA-48pq-2xq3-c2m4nvdWEB
- github.com/CoreWCF/CoreWCF/commit/6a99df3242f54acd6f89edfd6050430b72d0c685nvd
- github.com/CoreWCF/CoreWCF/commit/86dd3232b6b8aaf32281be9e8d798afad6145d58nvd
- github.com/CoreWCF/CoreWCF/commit/9eb9b46d1c2af06fb71f656a02f4d5b4649c1f03nvd
- github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1nvd
- github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1nvd
News mentions
1- CoreWCF: 13 CVEs Disclosed in a Single Day — Critical SAML Bypass and WS-Security FlawsVypr Intelligence · Jun 19, 2026