by Kastro
Paper/Archive/CVE-2026-54782

CVE-2026-54782

CoreWCF CoreWCF — CoreWCF: Authentication bypass in CoreWCF SAML 1.1 / 2.0 token signature validation

EPSS 0.4%CVSS 10.0
critical.is priorityof 100
37
CVSS 10.0 (CNA)10.0 / 10 × 3030.0Not in CISA KEV+300.0EPSS percentile 35.8.358 × 207.2No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
CoreWCF>= 1.9.0, < 1.9.1–CNA
CoreWCF< 1.8.1–CNA

Scores by source

GitHub_M (CNA)10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgithub.com/CoreWCF/CoreWCF/security/advisories/GHSA-xjr9-gg9q-jx3vrefgithub.com/CoreWCF/CoreWCF/commit/0b8c8af851260e85e8402af53233d1b8f87dfb6frefgithub.com/CoreWCF/CoreWCF/commit/0e63c2cca55763d8be6b226a234579280a09e7b6refgithub.com/CoreWCF/CoreWCF/commit/e5cc9b6a4ecc102a50d782093bfc72e0790abe3drefgithub.com/CoreWCF/CoreWCF/releases/tag/v1.8.1refgithub.com/CoreWCF/CoreWCF/releases/tag/v1.9.1