Ruby Activemodel Gem -- Circumvention of attr_protected

Aaron Patterson reports:

The attr_protected method allows developers to specify a blacklist
of model attributes which users should not be allowed to assign to.
By using a specially crafted request, attackers could circumvent
this protection and alter values that were meant to be protected.
All users running an affected release should either upgrade or use
one of the work arounds immediately. Users should also consider
switching from attr_protected to the whitelist method
attr_accessible which is not vulnerable to this attack.