CVE-2026-21715

A flaw in Node.js Permission Model filesystem enforcement leaves fs.realpathSync.native() without the required read permission checks, while all comparable filesystem functions correctly enforce them.

As a result, code running under --permission with restricted --allow-fs-read can still use fs.realpathSync.native() to check file existence, resolve symlink targets, and enumerate filesystem paths outside of permitted directories.

This vulnerability affects 20.x, 22.x, 24.x, and 25.x processes using the Permission Model where --allow-fs-read is intentionally restricted.