Group-Office is an enterprise customer relationship management and groupware tool. Prior to 6.8.150, 25.0.82, and 26.0.5, the MaintenanceController exposes an action zipLanguage which takes a lang parameter and passes it directly to a system zip command via exec(). This can be combined with uploading a crafted zip file to achieve remote code execution. This vulnerability is fixed in 6.8.150, 25.0.82, and 26.0.5.