High 7.4Published Jul 8, 2026

CVE-2026-54781CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced

Updated under an hour ago (Oct 28, 2026, 3:30 AM ET)

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Exploited in the last 30 days

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.

CVSS: 7.4 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-287, CWE-345
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jul 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

CoreWCF CoreWCF corewcf:corewcf (from the name)	from 1.9.0, < 1.9.1; before 1.8.1	CNA record

References

References

https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-48pq-2xq3-c2m4	x-refsource-confirm
https://github.com/CoreWCF/CoreWCF/commit/6a99df3242f54acd6f89edfd6050430b72d0c685	x-refsource-misc
https://github.com/CoreWCF/CoreWCF/commit/86dd3232b6b8aaf32281be9e8d798afad6145d58	x-refsource-misc
https://github.com/CoreWCF/CoreWCF/commit/9eb9b46d1c2af06fb71f656a02f4d5b4649c1f03	x-refsource-misc
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1	x-refsource-misc
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.