I have encountered this problem on 2 Mac computers now and thought it should be shared here since I can't find anyone asking this question.

After downloading and installing CubeIDE, when trying to launch the app, Mac says the app is damaged and needs to go into the trash. Redownloading and doing it again results in the same issue. To fix this problem, open Terminal and enter the following "xattr -cr /Application/STM32CubeIDE.app" This resets all the attributes within the package to allow the app to run.