CVE
CVE-2026-54782
CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation
Impact
Full impersonation of any principal the trusted STS could have issued an assertion for — including administrative principals when the relying party grants them via SAML claims. Affects both SAML 1.1 and SAML 2.0.
Preconditions
Relying-party service is hosted with WSFederationHttpBinding or WS2007FederationHttpBinding (or any binding that triggers FederatedSecurityTokenManager for issued-token validation), and IdentityConfiguration is wired (UseIdentityConfiguration = true).
Attacker can reach the service over the network and knows the trusted STS’s public certificate (public certs are by design discoverable).
Patches
Fixed in CoreWCF v1.8.1 and v1.9.1
Workarounds
None
Package Versions Affected
Package Version
patch Availability
No items found.
Automatically patch vulnerabilities without upgrading
Fix Without Upgrading
Detect compatible fix
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CVSS Version
Severity
Base Score
CVSS Version
Score Vector
C
H
U
10
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
C
H
U
10
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
Related Resources
No items found.
References
https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-xjr9-gg9q-jx3v, https://github.com/CoreWCF/CoreWCF