CVE-2026-54782 is a critical-severity security vulnerability in CoreWCF.Primitives (nuget), affecting versions < 1.8.1. It is fixed in 1.8.1, 1.9.1.
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
CVE-2026-54782 has a CVSS score of 10.0 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (1.8.1, 1.9.1). Upgrading removes the vulnerable code path.
nuget
CoreWCF.Primitives (< 1.8.1)CoreWCF.Primitives (>= 1.9.0, < 1.9.1)CoreWCF.Primitives → 1.8.1 (nuget)CoreWCF.Primitives → 1.9.1 (nuget)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-54782 is reachable in your applications. Explore open-source security for your team.
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Upgrade the following packages to resolve this vulnerability:
CoreWCF.Primitives to 1.8.1 or laterCoreWCF.Primitives to 1.9.1 or laterKodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-54782 is a critical-severity security vulnerability in CoreWCF.Primitives (nuget), affecting versions < 1.8.1. It is fixed in 1.8.1, 1.9.1.
CVE-2026-54782 has a CVSS score of 10.0 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
CoreWCF.Primitives (nuget) versions < 1.8.1 is affected.
Yes. CVE-2026-54782 is fixed in 1.8.1, 1.9.1. Upgrade to this version or later.
Whether CVE-2026-54782 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
CoreWCF.Primitives to 1.8.1 or laterCoreWCF.Primitives to 1.9.1 or later