CVE-2026-50202
Received Received - Intake
JWT Key Cache Bypass in Steeltoe Libraries

Publication date: 2026-06-17

Last updated on: 2026-06-17

Assigner: GitHub, Inc.

Description
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.
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Meta Information
Published
2026-06-17
Last Modified
2026-06-17
Generated
2026-06-18
AI Q&A
2026-06-18
EPSS Evaluated
N/A
NVD
CVE-2026-50202
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
steeltoe security.authentication.cloudfoundrybase to 3.4.0 (exc)
steeltoe security.authentication.jwtbearer to 4.2.0 (exc)
steeltoe security.authentication.openidconnect to 4.2.0 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-668 The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.
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Executive Summary

This vulnerability exists in Steeltoe's authentication libraries prior to certain versions. The JWT signing key cache in the TokenKeyResolver uses the 'kid' (key ID) as the sole cache key without differentiating by authority. In applications that use multiple JwtBearer schemes with different identity providers, a key fetched for one scheme can incorrectly validate tokens for another scheme.

Additionally, the cached keys do not expire, so if keys are rotated or revoked by an identity provider, the application continues to trust the old keys until it is restarted.

This issue is fixed in Steeltoe.Security.Authentication.CloudFoundryBase version 3.4.0, JwtBearer version 4.2.0, and OpenIdConnect version 4.2.0.

If immediate upgrading is not possible, it is recommended to configure only one JwtBearer scheme per application when using different identity providers, or to restart the application after key rotations to clear stale cached keys.

Impact Analysis

This vulnerability can lead to improper token validation in applications using multiple JwtBearer authentication schemes with different identity providers.

A key fetched for one identity provider could be used to validate tokens from another, potentially allowing unauthorized access.

Furthermore, because cached keys do not expire, revoked or rotated keys remain trusted until the application restarts, increasing the risk of accepting invalid or compromised tokens.

Mitigation Strategies

To mitigate this vulnerability immediately, you should upgrade to Steeltoe.Security.Authentication.CloudFoundryBase version 3.4.0, Steeltoe.Security.Authentication.JwtBearer version 4.2.0, or Steeltoe.Security.Authentication.OpenIdConnect version 4.2.0, which contain the patch.

If an immediate upgrade is not possible, you can take the following steps:

  • 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.
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