An important WHMCS Security Update was released on 2021-02-26 by WHMCS.
WHMCS Security Update 2021-02-26
The security issue is known to affect all versions of WHMCS released up to this date.
WHMCS has 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 by WHMCS Security Bounty Program and WHMCS announced that there is no evidence to suggest that this security issue is known to the public. WHMCS will not be releasing any further details about the security issue at this time. This is probably best to protect active WHMCS installations have not yet applied the patch/update that fix this security issue.
What is the recommended action by WHMCS?
Users of WHMCS 7.10, 8.0 or 8.1 can upgrade to WHMCS 8.1.3 released 26th Feb 2021 to resolve the security issue, WHMCS recommends using the Automatic Updater to update. If you want to manually update you can download WHMCS from the official link below.
WHMCS 8.1 Release Notes
https://docs.whmcs.com/Version_8.1.0_Release_Notes
Users of WHMCS 7.7, 7.8 and 7.9 can download and apply the patch which has been made available from the link below.
https://download.whmcs.com/#patch
WHMCS recommends users of WHMCS 7.6 and earlier to update to WHMCS 7.10 or later.
It is recommended that you upgrade or apply the appropriate patch as soon as possible.
Detailed Update Instructions by WHMCS
Below is a direct link to the official WHMCS blog post about this security update, it also contains details instructions on how to update or patch your WHMCS installation.
https://blog.whmcs.com/133679/security-update-2021-02-26
Need Help?
If you have any issues updating your WHMCS installation or applying the patch, you can contact our support team at https://greens247.com/support/