Hashgraph Guardian through version 3.5.0 contains an unsandboxed JavaScript execution vulnerability in the Custom Logic policy block worker that allows authenticated Standard Registry users to execute arbitrary code by passing user-supplied JavaScript expressions directly to the Node.js Function() constructor without isolation. Attackers can import native Node.js modules to read arbitrary files from the container filesystem, access process environment variables containing sensitive credentials such as RSA private keys, JWT signing keys, and API tokens, and forge valid authentication tokens for any user including administrators.

A Stored HTML Injection vulnerability was discovered in the Alerted Nodes Dashboard functionality due to improper validation on an input parameter. A malicious authenticated user with the required privileges could edit a node label to inject HTML tags. If the system is configured to use the Alerted Nodes Dashboard, and alerts are reported for the affected node, then the injected HTML may render in the browser of a victim user interacting with it, enabling phishing and possibly open redirect attacks. Full XSS exploitation and direct information disclosure are prevented by the existing input validation and Content Security Policy configuration.