Valve Steam 3.42.16.13 uses weak permissions for the files in the Steam program directory, which allows local users to modify the files and possibly gain privileges as demonstrated by a Trojan horse Steam.exe file.

Valve Bug Reporter in the valve-bugreporter package 2.10+bsos1 in Valve SteamOS Beta stores cleartext credentials in a .valve-bugreporter.cfg file upon a Remember Credentials action, which allows local users to obtain sensitive information by reading this file.