Running a command remotely using ksh

I want to loop through all of our Solaris servers using ssh and make sure the patch for shellshock has been applied.  The check for it is this:
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"

if it prints "vulnerable", you need to have the patch applied.  The problem is that the special characters in that command break when I run through a list of our servers in a for loop trying to ssh to them.  I've tried \ them out, but to no avail.

The loop looks like this:
for i in $serverlist)
do
      ssh $i env x='() { :;}; echo vulnerable' bash -c "echo this is a test" |grep vulnerable
      if [ $? -eq 0 ]
      then
              print $i needs patch
      fi
done



Any help would be appreciated.

David