WHMCS has released new updates for all supported versions of WHMCS. These updates include changes that address security concerns within the WHMCS product.

WHMCS has rated these updates as having a moderate to trivial security impact. Information on security ratings can be found at https://docs.whmcs.com/Security_Levels

Please update your installation to one of the following versions:
v5.3.6v5.2.17


- What is a Patch?
Incremental patches can be downloaded by following the links below.

These patch sets contain only the files that have changed between the previous release and this update. The previous release version that these patch sets are designed for is clearly indicated as the first and smaller number.
[INDENT]
5.3.5 --> 5.3.6 https://go.whmcs.com/378/v535_incremental_to_v536_patch[size=1]MD5 Checksum: 42dd3cd44e1fc9308e9b7ecb0a3b956d[/size]
5.2.16 --> 5.2.17 https://go.whmcs.com/374/v5216_incremental_to_v5217_patch[size=1]MD5 Checksum: 542b2eb940066317d3190e2cf9986ee0[/size][/INDENT]

Need a patch for an older version? Visit our downloads page: https://download.whmcs.com/

To apply a patch set release, download the files as indicated above. Then follow the upgrade instructions for a "Patch Set" which can be found at https://docs.whmcs.com/Upgrading#For_a_Patch_Set


- What is a Full Release?
A full release distribution contains all the files of a WHMCS product installation. It can be used to both perform a new installation or update an existing one (regardless of previous version).
[INDENT]
5.3.6 Full Version - Download Now https://download.whmcs.com/[size=1]MD5 Checksum: 4a136a87e2c360350daa2cf7d8b7a048[/size][/INDENT]

To apply a full release, download the release from the URL above. Then follow the upgrade instructions for a "Full Release Version" which can be found at https://docs.whmcs.com/Upgrading#For_a_Full_Release_Version



The security changes in these releases address 11 privately reported issues through our security bounty program, and 1 issue discovered internally by the WHMCS Development Team. The issues addressed are rated as having Moderate to Trivial security impact.

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 issues.



This release also provides resolution for a number of maintenance issues. For full details please refer to the change logs for each respective version:
[INDENT]
V5.3.6 - https://changelog.whmcs.com/WHMCS_V5.3V5.2.17 - https://changelog.whmcs.com/WHMCS_V5.2[/INDENT]

All published and supported versions of WHMCS prior to 5.3.6 are affected by one or more of these maintenance and security issues.