When uploading a file in Sysax Multi Server 6.90, an authenticated user can modify the filename="" parameter in the uploadfile_name1.htm form to a length of 368 or more bytes. This will create a buffer overflow condition, causing the application to crash.

An issue was discovered in Sysax Multi Server 6.90. A session can be hijacked if one observes the sid value in any /scgi URI, because it is an authentication token.

An issue was discovered in Sysax Multi Server 6.90. An attacker can determine the username (under which the web server is running) by triggering an invalid path permission error. This bypasses the fakepath protection mechanism.

An issue was discovered in Sysax Multi Server 6.90. There is reflected XSS via the /scgi sid parameter.