How can the use of register_globals impact the functionality of PHP scripts, as seen in the provided code snippet?

When register_globals is enabled in PHP, it can lead to security vulnerabilities as it allows external variables to overwrite internal variables, potentially leading to unintended behavior or injection attacks. To solve this issue, it is recommended to disable register_globals in the php.ini configuration file.

// Disable register_globals in php.ini configuration file
// Change register_globals = On to register_globals = Off