CVE-2026-54774CWE-345CWE-347

CoreWCF: SamlSerializer skips SignatureValue verification when SAML signing token is not an X.509 certificate

High · published July 8, 2026

CVSS v3.1
7.4
EPSS
0%
Percentile
9.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.4 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00203 · 9.7th percentile
Weaknesses
CWE-345 · Insufficient Verification of Data Authenticity; CWE-347 · Improper Verification of Cryptographic Signature
Published
2026-07-08T22:17Z
EPSS history
Timeline
  • 08 JUL 22:17Z
    CoreWCF: SamlSerializer skips SignatureValue verification when SAML signing token is not an X.509 certificate
    cvelistv5