vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.0, vm2's CallSite wrapper class (intended as a safe wrapper for V8's native CallSite) blocks getThis() and getFunction() to prevent host object leakage, but allows getFileName() to return unsanitized host absolute paths. Any sandboxed code can extract the full directory structure, library paths, and framework versions of the host server. This vulnerability is fixed in 3.11.0.