CVE-2026-71269: Node-RED Library API Path Traversal Leading to Arbitrary File Read/Write

Node-RED's local-filesystem library storage module (getLibraryEntry() and saveLibraryEntry() in packages/nodemodules/@node-red/runtime/lib/storage/localfilesystem/library.js), reachable via GET/POST /library/:lib/:type/path, joins the user-supplied path parameter directly into the filesystem path via fspath.join(libDir, type, path) with no traversal sanitization, containment check, or path normalization/prefix verification. An authenticated user (including read-only-scoped tokens for the read path) can supply a path containing ../ sequences to read arbitrary files outside the library directory; a user with write access can write arbitrary files, enabling remote code execution via SSH authorizedkeys or cron injection. This is a distinct, separately unpatched traversal from the previously fixed CVE-2021-21298 (Projects API).