GHSA-88pr-878c-24wf

## Summary Flowise on current `main` allows an authenticated user with `documentStores:preview-process` permission to trigger the `S3 Directory` document loader with attacker-controlled S3 object keys. The loader joins each returned S3 key with a temporary directory using `path.join(tempDir, key)` and writes the object bytes to disk **without validating traversal sequences such as `../`**. Cleanup later removes only the original temporary directory, so files written outside that directory persist on the host filesystem. This yields **arbitrary file write** with the privileges of the Flowise server process.