Exposure of Sensitive Information to an Unauthorized Actor
Ultimate PHP Board (UPB) 1.0 allows remote attackers to view the physical path of the message board via a direct request to add.php, which leaks the path in an error message.
CWE-200 - Information Exposure
An information exposure vulnerability is categorized as an information flow (IF) weakness, which can potentially allow unauthorized access to otherwise classified information in the application, such as confidential personal information (demographics, financials, health records, etc.), business secrets, and the application's internal environment.