Steeltoe's static JWKS cache shared across schemes and never invalidated

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-50202: 0.29% estimated exploitation activity in the next 30 days; percentile 21.60 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

2 Jul 2026, 20:31 UTC

Last modified by the source

2 Jul 2026, 20:31 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7fqc-p256-7pwj

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# Patch Next advisory brief: CVE-2026-50202

Advisory: Steeltoe's static JWKS cache shared across schemes and never invalidated
IDs: CVE-2026-50202, GHSA-7fqc-p256-7pwj
Record: https://patchnext.com/advisories/cve-2026-50202 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: steeltoe.security.authentication.cloudfoundrybase 3.4.0; steeltoe.security.authentication.jwtbearer 4.2.0; steeltoe.security.authentication.openidconnect 4.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet steeltoe.security.authentication.cloudfoundrybase: affected <= 3.3.0; fixed in 3.4.0
- NuGet steeltoe.security.authentication.jwtbearer: affected <= 4.1.0; fixed in 4.2.0
- NuGet steeltoe.security.authentication.openidconnect: affected <= 4.1.0; fixed in 4.2.0

## Suggested inspection (read-only)
- NuGet steeltoe.security.authentication.cloudfoundrybase: check the installed version with your package manager.
- NuGet steeltoe.security.authentication.jwtbearer: check the installed version with your package manager.
- NuGet steeltoe.security.authentication.openidconnect: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on steeltoe.security.authentication.cloudfoundrybase, steeltoe.security.authentication.jwtbearer, steeltoe.security.authentication.openidconnect.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7fqc-p256-7pwj (GitHub-reviewed advisory GHSA-7fqc-p256-7pwj lists affected ranges: NuGet steeltoe.security.authentication.jwtbearer >=0 =0 =0 <=3.3.0)

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