INJ-005critical SeverityInjection Sinks & Input Validation
Path Traversal Prevention on File Downloads and Uploads
Agents read files using path.join(uploadDir, req.query.file) without stripping ../ sequences, allowing attackers to read system files.
1-Click Fix Prompt for Cursor & Claude Code
Review my codebase for "Path Traversal Prevention on File Downloads and Uploads" (INJ-005). Issue: Agents read files using path.join(uploadDir, req.query.file) without stripping ../ sequences, allowing attackers to read system files. Remediation required: Sanitize file paths by stripping non-alphanumeric characters or verify path.resolve stays inside the intended root directory. Please: 1. Locate any occurrences of this issue across my repository. 2. Refactor the code to follow production standards without breaking existing functionality. 3. Provide a clear command or step to test and verify the fix.
Why AI Assistants Write This Bug
Agents read files using path.join(uploadDir, req.query.file) without stripping ../ sequences, allowing attackers to read system files.
AI code generation prioritizes immediate syntax execution over production edge cases. When an assistant hits an undefined variable or strict type error, it frequently takes the path of least resistance rather than implementing standard pre-launch security patterns.
Code Comparison
Common AI Code PatternVulnerable
// Vulnerable AI-generated pattern for: Path Traversal Prevention on File Downloads and Uploads
// Problematic pattern: Agents read files using path.join(uploadDir, req.query.file) without stripping ../ sequences, allowing attackers to read system files.Launch-Ready Fix
// Production-ready fix for: Path Traversal Prevention on File Downloads and Uploads
// Recommended remediation: Sanitize file paths by stripping non-alphanumeric characters or verify path.resolve stays inside the intended root directory.Remediation & Verification Checklist
Remediation: Sanitize file paths by stripping non-alphanumeric characters or verify path.resolve stays inside the intended root directory.
- Search your codebase for pattern matching "Path Traversal Prevention on File Downloads and Uploads".
- Apply the recommended remediation: Sanitize file paths by stripping non-alphanumeric characters or verify path.resolve stays inside the intended root directory.
- Run local build and test commands to ensure no regressions.
- Verify in your browser or with curl that the issue is resolved.
Audit All 108 Checks in One Click
Checking items one by one takes hours. Let us do it in 2 minutes.
With the Founder Pass ($15 one-time), we automatically scan your repository for this issue, plus all other 107 launch checks across secrets, Stripe webhooks, Supabase RLS, and security headers.