CVE-2026-50202
MediumCVSS 5.9Exploitation Probability (EPSS)
Low risk20th percentile — higher than 20% of all known CVEs
Summary
In Steeltoe projects prior to versions 3.4.0 (CloudFoundryBase), 4.2.0 (JwtBearer), and 4.2.0 (OpenIdConnect), there is an issue with the JWT signing key cache. The `kid` is used as the sole cache key, which can lead to unauthorized token validation in applications with multiple `JwtBearer` schemes pointing to different identity providers.
Risk Assessment
The organization may be exposed to attacks where signing keys from one identity provider are used to validate tokens from another, potentially leading to unauthorized access. Additionally, the lack of expiration for cached keys increases the risk associated with key rotation or revocation.
Recommendation
Immediate upgrade to versions 3.4.0 (CloudFoundryBase), 4.2.0 (JwtBearer), and 4.2.0 (OpenIdConnect) is recommended. If an upgrade is not possible, configure only one `JwtBearer` scheme per application when different identity providers are required and restart the application process after an identity provider signing key rotation.
Original NVD description (English source)
Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. In Steeltoe.Security.Authentication.CloudFoundryBase prior to version 3.4.0, Steeltoe.Security.Authentication.JwtBearer prior to version 4.2.0, and Steeltoe.Security.Authentication.OpenIdConnect prior to version 4.2.0, 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. Steeltoe.Security.Authentication.CloudFoundryBase version 3.4.0, Steeltoe.Security.Authentication.JwtBearer version 4.2.0, and Steeltoe.Security.Authentication.OpenIdConnect version 4.2.0 patch the issue. If an immediate upgrade is not possible: In multi-scheme deployments, configure only one `JwtBearer` scheme per application when different identity providers are required; and/or restart the application process after an identity provider signing key rotation to clear stale cached keys.