Course

The Code Review Patch challenges are designed to enhance your skills in identifying vulnerabilities by examining both the flawed code and its patch. Initially, you should strive to find the issue without referring to the patch; however, the patch is available for confirmation or if you encounter difficulties. In this specific challenge, your goal is to locate the line where the value is retrieved rather than where it is utilized.

The provided code snippet from `phpBB/viewtopic.php` demonstrates a vulnerability related to the improper handling of user input—specifically, the `highlight` parameter. The patch addresses this issue by modifying the way special characters are escaped, ensuring that user input is properly sanitized. This exercise is crucial for understanding common vulnerabilities and the importance of secure coding practices.