Exposure of Sensitive Information to an Unauthorized Actor
Wiki Server in Apple Mac OS X 10.5 before 10.5.3 allows remote attackers to obtain sensitive information (user names) by reading the error message produced upon access to a nonexistent blog.
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.