As you may be aware, a security issue has been published which affects all known versions of WHMCS.

We are currently aware of the issue and are working on a software update to prevent this attack vector from being successful.

We will be publishing software updates for the versions in Active Development and LTS per our Long Term Support Policy:

https://docs.whmcs.com/Long_Term_Support
Please keep watch on our blog, facebook and twitter to receive the latest updates.