CVE-2026-50202 is a medium-severity security vulnerability in Steeltoe.Security.Authentication.JwtBearer (nuget), affecting versions <= 4.1.0. It is fixed in 4.2.0, 3.4.0.
Summary The JWT signing key cache in TokenKeyResolver uses kid as the sole cache key without namespacing by authority. In applications with multiple JwtBearer schemes pointing to different identity providers, a key fetched for one scheme can satisfy token validation for another. Additionally, cached keys have no expiration, so rotated or revoked keys remain trusted until the application process restarts. Impact In multi-scheme deployments, an attacker who controls one identity provider's signing key can forge tokens accepted by other schemes within the same application. For all applications using TokenKeyResolver, a signing key removed from the identity provider's JWKS endpoint remains trusted indefinitely. Mitigations If an immediate upgrade is not possible: In multi-scheme deployments, configure only one JwtBearer scheme per application when different identity providers are required. Restart the application process after an identity provider signing key rotation to clear stale cached keys.
CVE-2026-50202 has a CVSS score of 5.9 (Medium). The vector is network-reachable, high 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 (4.2.0, 3.4.0). Upgrading removes the vulnerable code path.
nuget
Steeltoe.Security.Authentication.JwtBearer (<= 4.1.0)Steeltoe.Security.Authentication.OpenIdConnect (<= 4.1.0)Steeltoe.Security.Authentication.CloudFoundryBase (<= 3.3.0)Steeltoe.Security.Authentication.JwtBearer → 4.2.0 (nuget)Steeltoe.Security.Authentication.OpenIdConnect → 4.2.0 (nuget)Steeltoe.Security.Authentication.CloudFoundryBase → 3.4.0 (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-2026-50202 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-50202 is reachable in your applications. Get a demo
Already deployed Kodem? See CVE-2026-50202 in your environment →Upgrade the following packages to resolve this vulnerability:
Steeltoe.Security.Authentication.JwtBearer to 4.2.0 or laterSteeltoe.Security.Authentication.OpenIdConnect to 4.2.0 or laterSteeltoe.Security.Authentication.CloudFoundryBase to 3.4.0 or laterKodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-50202 is a medium-severity security vulnerability in Steeltoe.Security.Authentication.JwtBearer (nuget), affecting versions <= 4.1.0. It is fixed in 4.2.0, 3.4.0.
CVE-2026-50202 has a CVSS score of 5.9 (Medium). 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.
Steeltoe.Security.Authentication.JwtBearer (nuget) (versions <= 4.1.0)Steeltoe.Security.Authentication.OpenIdConnect (nuget) (versions <= 4.1.0)Steeltoe.Security.Authentication.CloudFoundryBase (nuget) (versions <= 3.3.0)Yes. CVE-2026-50202 is fixed in 4.2.0, 3.4.0. Upgrade to this version or later.
Whether CVE-2026-50202 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.
Steeltoe.Security.Authentication.JwtBearer to 4.2.0 or laterSteeltoe.Security.Authentication.OpenIdConnect to 4.2.0 or laterSteeltoe.Security.Authentication.CloudFoundryBase to 3.4.0 or later