CVE-2026-30887: OneUpTime's Unsandboxed Code Execution in Probe Allows Any Project Member to Achieve RCE

OneUptime allows project members to run custom Playwright/JavaScript code via Synthetic Monitors to test websites. However, the system executes this untrusted user code inside the insecure Node.js vm module. By leveraging a standard prototype-chain escape (this.constructor.constructor), an attacker can bypass the sandbox, gain access to the underlying Node.js process object, and execute arbitrary system commands (RCE) on the oneuptime-probe container. Furthermore, because the probe holds database/cluster credentials in its environment variables, this directly leads to a complete cluster compromise.