We have released a Firefox 27 compatibility patch for Norton Internet Security 126.96.36.199, Norton 360 188.8.131.52, andComcast Norton Security Suite 184.108.40.206 which is available via LiveUpdate. The patch is also available for the Norton 2013, Norton 2012, and Norton Identity Safe standalone product.
The versions for this compatibility update are as follows:
Norton Internet Security, Norton 360 & Comcast Norton Security Suite v 220.127.116.11
Norton Toolbar: 2014.6.5.1
Note: For the 21.x update, this patch does not require reboot on Win7 & Win 8 machines.