What is the potential issue with using $_PHP_SELF in a form action attribute in PHP?

Using $_PHP_SELF in a form action attribute in PHP can pose a security risk as it makes the form vulnerable to cross-site scripting attacks. To solve this issue, it is recommended to use htmlspecialchars() function to escape special characters in the $_PHP_SELF variable before using it in the form action attribute. 

<form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']); ?>" method="post">
    <!-- Form fields here -->
</form>

Keywords

$_PHP_SELF form action attribute security vulnerability cross-site scripting (XSS) user input validation

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