Esri Portal for ArcGIS: missing authentication

Esri Portal for ArcGIS versions 12.1 and earlier on Windows, Linux and Kubernetes have a missing authentication for critical function vulnerability allows a remote, unauthenticated attacker to access an unprotected API. The following versions are known to be affected: Portal for ArcGIS 12.1 and earlier. Other unsupported versions may also be affected. Esri recommends that users apply the Portal for ArcGIS Security 2026 Update 2 Patch to remediate this vulnerability.