Exposure of Sensitive Information to an Unauthorized Actor
core/string_api.php in Mantis before 1.1.3 does not check the privileges of the viewer before composing a link with issue data in the source anchor, which allows remote attackers to discover an issue's title and status via a request with a modified issue number.
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.