CVE-2026-67531 FrontMCP: CodeCall sandbox escape -> host RCE via live Zod schema exposure by getTool

FrontMCP is a TypeScript-first framework for the Model Context Protocol MCP. Prior to 1.5.7, the sandboxed codecall:execute tool exposes live host Zod schema instances to the script via getTool, and because Zod v4 defines zod as a non-configurable, non-writable own property, the ECMAScript Proxy...

CVE-2026-67531

CVE-2026-67531 affects FrontMCP before 1.5.7. The sandboxed codecall:execute tool could leak live host Zod schema instances to scripts via getTool, and due to Zod v4 _zod being non-configurable/non-writable, the ECMAScript Proxy invariant returned the raw host object. This allowed a script to rea...