In version 6.13.0 of LimeSurvey, any external user can cause a 500 error in the survey system by sending a malformed session cookie. Instead of displaying a generic error message, the system exposes internal backend information, including the use of the Yii framework, the MySQL/MariaDB database engine, the table name 'lime_sessions', primary keys, and fragments of the content that caused the conflict. This information can simplify the collection of data about the internal architecture of the application by an attacker.