Vulnerability · Published Jun 17, 2026 · Assigned by GitHub_M
CVE-2026-50202Steeltoe's static JWKS cache shared across schemes and never invalidated
Medium 5.9
In plain English
A medium-severity security flaw in Steeltoe.Security.Authentication.CloudFoundryBase from SteeltoeOSS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| NuGet | steeltoe.security.authentication.cloudfoundrybase | 3.4.0 | GHSA-7fqc-p256-7pwj |
| NuGet | steeltoe.security.authentication.jwtbearer | 4.2.0 | GHSA-7fqc-p256-7pwj |
| NuGet | steeltoe.security.authentication.openidconnect | 4.2.0 | GHSA-7fqc-p256-7pwj |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| SteeltoeOSS | Steeltoe.Security.Authentication.CloudFoundryBase | < 3.4.0 |
| SteeltoeOSS | Steeltoe.Security.Authentication.JwtBearer | < 4.2.0 |
| SteeltoeOSS | Steeltoe.Security.Authentication.OpenIdConnect | < 4.2.0 |
Weakness: CWE-668 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N
References
- https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-7fqc-p256-7pwj x_refsource_CONFIRM
- https://github.com/SteeltoeOSS/Steeltoe/commit/04db2ace3b806bfe0260bb7d4bda340f241eff48 x_refsource_MISC
- https://github.com/SteeltoeOSS/Steeltoe/commit/17b27b8be546ae3f83a2f6e91d45e0c84c5314b7 x_refsource_MISC