The to_s method in actionpack/lib/action_dispatch/middleware/remote_ip.rb in Ruby on Rails 3.0.5 does not validate the X-Forwarded-For header in requests from IP addresses on a Class C network, which might allow remote attackers to inject arbitrary text into log files or bypass intended address parsing via a crafted header.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.