A race condition in Guacamole's terminal emulator in versions 0.9.5 through 0.9.10-incubating could allow writes of blocks of printed data to overlap. Such overlapping writes could cause packet data to be misread as the packet length, resulting in the remaining data being written beyond the end of a statically-allocated buffer.

Cross-site scripting (XSS) vulnerability in the file browser in Guacamole 0.9.8 and 0.9.9, when file transfer is enabled to a location shared by multiple users, allows remote authenticated users to inject arbitrary web script or HTML via a crafted filename. NOTE: this vulnerability was fixed in guacamole.war on 2016-01-13, but the version number was not changed.

Stack-based buffer overflow in the guac_client_plugin_open function in libguac in Guacamole before 0.6.3 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a long protocol name.