CVE-2026-54774
Prior to 1.8.1 and 1.9.1, SamlSerializer skips final SignatureValue verification when a CoreWCF service validates SAML tokens using a non-X.509 signing token, allowing an attacker to reference a non-X.509 SecurityToken key identifier and bypass…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.20%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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, SamlSerializer skips final SignatureValue verification when a CoreWCF service validates SAML tokens using a non-X.509 signing token, allowing an attacker to reference a non-X.509 SecurityToken key identifier and bypass assertion signature verification. This issue is fixed in versions 1.8.1 and 1.9.1.
- CVSS 3.1
- 7.4 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.20% probability · 10th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-345, CWE-347
- Source
- security-advisories@github.com
References
- https://github.com/CoreWCF/CoreWCF/commit/65d09022749854ba943e376aefb958dec05b00d8
- https://github.com/CoreWCF/CoreWCF/commit/b914495ce63c44924664643b60a262e7595081a4
- https://github.com/CoreWCF/CoreWCF/commit/e7454132876ecc7e2cf80e541a44376eeb54979b
- https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1
- https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1
- https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-rpj7-hr7h-w6p9
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.