# CVE-2026-54782

## Summary

- **CVE ID:** CVE-2026-54782
- **Severity:** CRITICAL
- **CVSS Score:** 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N)
- **CWE:** CWE-290, CWE-347
- **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. Prior to 1.8.1 and 1.9.1, CoreWCF SAML 1.1 and SAML 2.0 token validation does not correctly resolve the issuer signing key or require signed tokens when IdentityConfiguration is used with federated bindings, allowing an unauthenticated remote attacker to impersonate any principal the trusted STS could issue. This issue is fixed in versions 1.8.1 and 1.9.1.

## Affected Products

- CoreWCF — CoreWCF (>= 1.9.0, < 1.9.1)
- CoreWCF — CoreWCF (< 1.8.1)

## References

- [CNA](https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1)
- [CNA](https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-xjr9-gg9q-jx3v)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/0b8c8af851260e85e8402af53233d1b8f87dfb6f)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/0e63c2cca55763d8be6b226a234579280a09e7b6)
- [CNA](https://github.com/CoreWCF/CoreWCF/commit/e5cc9b6a4ecc102a50d782093bfc72e0790abe3d)
- [CNA](https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.41%
- **EPSS Percentile:** 35.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._