Deno is a JavaScript, TypeScript, and WebAssembly runtime. Starting in version 1.36.2 and prior to version 1.40.3, use of inherently unsafe "*const c_void" and "ExternalPointer" leads to use-after-free access of the underlying structure, resulting in arbitrary code execution. Use of inherently unsafe "*const c_void" and "ExternalPointer" leads to use-after-free access of the underlying structure, which is exploitable by an attacker controlling the code executed inside a Deno runtime to obtain arbitrary code execution on the host machine regardless of permissions. This bug is known to be exploitable for both "*const c_void" and "ExternalPointer" implementations. Version 1.40.3 fixes this issue.