Exposure of Sensitive Information to an Unauthorized Actor
The web framework in Cisco WebEx Meetings Server produces different returned messages for URL requests depending on whether a username exists, which allows remote attackers to enumerate user accounts via a series of requests, aka Bug ID CSCuj40247.
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.