This article aims at explaining and exploring the vulnerability in the input() function in Python 2.x. In Python 3, the raw_input() function was erased, and its functionality was transferred to a new built-in function known as input().

In Python 2.x, the input() function is vulnerable to security risks. The input() function reads a line from the user's input and evaluates it as a Python expression. This means that a user can execute arbitrary code by entering it as input to the input() function.

For example, if a user inputs the following code: 

__import__('os').system('rm -rf /')

The input() function will evaluate it as a Python expression and execute it, resulting in the deletion of all files on the root directory.

To prevent this vulnerability, it is recommended to use the raw_input() function instead of input() in Python 2.x. The raw_input() function reads a line from the user's input as a string, rather than evaluating it as a Python expression.

For example: 

name = raw_input("Enter your name: ")

This code will read a string input from the user and assign it to the variable name.

It is also important to sanitize user input by checking for unexpected characters and restricting input to only certain types of data. This can help prevent malicious code execution and other security risks.