Disallow root escalation by creating /var/lib/chromeos-aliases.conf and inserting commands. [Credit to Chrome OS Team (Sean Paul)]
Disallow modification of about:flags in Guest mode [Credit to Chrome OS Security Team (Jim Hebert)]
Multiple package updates (openssl, dbugs, pango, sudo, strongswan, acl, libxml2, dhcpd) [Credit to Chrome OS Security Team]