Although the risk to firewalled systems is low, we have released a patch to remove this vulnerability from all mutiny appliances.
The patch can be downloaded from here and applied through the maintenance interface as per normal updates.
Please remember to download the patch with "Save as" and select all files and ensure the filename ends in .gpg (not .gz)
The CERT advisory can be found here
https://www.cert.gov.uk/resources/alerts/update-bash-vulnerability-aka-shellshock/