A security issue has been identified that affects all versions of WHMCS.
As a result, we have published new releases for all actively supported versions of WHMCS as well as a patch which can be applied to EOL versions 7.7, 7.8 and 7.9. Patches will not be released for any earlier versions of WHMCS.
The issue was reported via our Security Bounty Program and there is no evidence to suggest it is known publicly. We will not be releasing any further details about the issue at this time.
