Google Chrome OS before R12 0.12.433.38 Beta allows local users to gain privileges by creating a /var/lib/chromeos-aliases.conf file and placing commands in it.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2011-2161
http://googlechromereleases.blogspot.com/2011/05/chrome-os-beta-channel-update_16.html