stconf.nsf in IBM Sametime Meeting Server 8.5.1 relies on the client to validate the file format used in wAttach?OpenForm multipart/form-data POST requests, which allows remote authenticated users to bypass intended upload restrictions by modifying the Content-Type header and file extension, as demonstrated by replacing a text/plain .txt upload with an application/octet-stream .exe upload.

Multiple cross-site scripting (XSS) vulnerabilities in the Classic Meeting Server in IBM Sametime 7.5.1.2 through 8.5.2.1 allow remote authenticated users to inject arbitrary web script or HTML via unspecified vectors.