File existence oracle information disclosure in OpenClaw tools.exec.safeBins

This repository is a small proof-of-concept exploit/demo for a race condition in a Flask file upload workflow, labeled as CVE-2026-4040. It contains two Python programs: `upload_server.py`, which implements the intentionally vulnerable Flask upload service, and `exploit_race_upload.py`, which submits a crafted upload and concurrently scans for temporary files to exploit the time-of-check/time-of-use gap. The vulnerable server writes an uploaded file to a temporary path under `/tmp/uploads` using `tempfile.mkstemp`, then validates only that the original filename ends with `.txt`, sleeps for 0.5 seconds, and finally renames the temporary file to its final name. This creates a race window where attacker-controlled content exists on disk before validation/move completes. The exploit uploads a file named `payload.py.txt` containing Python code `import os; os.system("id > /tmp/pwned")`, which is intended to masquerade as an allowed text file while still carrying executable content. The exploit capability is limited but clear: it demonstrates arbitrary command execution by planting a script payload and attempting to access temporary files matching `/tmp/uploads/tmp*` during the vulnerable window. In the provided code, the `execute_temp()` thread only scans and opens candidate temp files and does not actually trigger remote execution via a web server; comments indicate that in a real attack this step would involve repeatedly requesting or executing the temporary file through another reachable execution path. As such, the repository is best understood as an operational demo of the race/upload primitive and payload staging rather than a fully weaponized end-to-end RCE exploit. Repository structure is minimal: `README.md` explains the vulnerability and usage, `upload_server.py` is the vulnerable target, `exploit_race_upload.py` is the attacker script, and `LICENSE` is standard MIT text. No external exploit framework is used.