There is a code injection vulnerability in Esri Portal for ArcGIS versions 10.8.1 and below that may allow a remote, unauthenticated attacker to pass strings which could potentially cause arbitrary code execution.
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.