WHMCS has released new patches for the 4.5, 5.0, 5.1, and 5.2 minor releases. These updates provide targeted changes to address security concerns with the WHMCS product. You are highly encouraged to update immediately.

WHMCS has rated these updates as including critical or important security impacts. Information on security ratings is available at https://docs.whmcs.com/Security_Levels.

The following full-release versions of WHMCS have been published and address all known vulnerabilities:
5.2.6

The latest public releases of WHMCS are available inside our members area at https://www.whmcs.com/members/clientarea.php

PLEASE NOTE: The 4.5 series reached End Of Life as of June 30th 2013. WHMCS is aware that some customers have not moved to an LTS version due to the newness of the LTS policy. The related 4.5 patch release published along with this Security Advisory is provided as a courtesy to those customers. From this point forward, there will be no more patches provided for 4.5 or any other release that has reached EOL.
The resolved security issues were identified and reported by
Vlad C. of NetSec Interactive Solutions https://safeornot.net
Rack911 https://www.rack911.com
FastVPS Eesti OU https://fastvps.ru
WHMCS development team.

There is no reason to believe that these vulnerabilities are known to the public. As such, WHMCS will only release limited information regarding the vulnerabilities at this time.

Once sufficient time has passed to allow WHMCS customers to update their installed software, WHMCS will release additional information regarding the nature of the security issue.

These Targeted Security Releases and Patches address 9 vulnerabilities in WHMCS versions 4.5, 5.0, .5.1, and 5.2.


WHMCS Version 4.5Download and apply the appropriate patch files to protect against these vulnerabilities.

Patch files for affected versions of the 4.5 series are located on the WHMCS site as itemized below.

v4.5.6 (patch only; for 4.5.5) - https://go.whmcs.com/174/v456patch

To apply a patch, download the files as indicated above. Next follow the regular upgrade instructions which can be found at https://docs.whmcs.com/Upgrading#Performing_an_Upgrade.

WHMCS Version 5.xDownload and apply the appropriate full-version or patch of WHMCS to protect against these vulnerabilities.

Patch files for affected version 5.x are located on the WHMCS site as itemized below. A full-version of 5.2.6 is located in the WHMCS member's area download section, under your license details.

v5.0.7 (patch only; for 5.0.6) - https://go.whmcs.com/178/v507patch
v5.1.8 (patch only; for 5.1.7) - https://go.whmcs.com/182/v518patch
v5.2.6 (full-version) - Available in the members area

To apply a patch or full-version release, download the files as indicated above. Next follow the regular upgrade instructions which can be found at https://docs.whmcs.com/Upgrading#Performing_an_Upgrade.

*This Security Advisory is in the process of being emailed to all active license holders.*