WHMCS 8.13.1 Security Update

8.13.1 (Maintenance) Security Fixes

WHMCS 8.13.1 is a security maintenance release. It bundles a number of security hardening changes. Below is an explanation of what each fix addresses, along with the affected versions and the update path.

Honour parent theme definition for captcha.tpl on Login as Owner link

The login-as-owner flow now respects the parent theme’s CAPTCHA template definition, closing a gap where the CAPTCHA could be skipped.

Undisclosed Security Fix

WHMCS ships several security fixes each release without publishing technical detail. These are applied as hardening of the platform and are not accompanied by a public CVE, so the specific mechanism is withheld to protect installations that have not yet updated. Upgrading is the recommended course of action.

Affected Versions and Remediation

Apply the update to the latest patch release of your WHMCS branch. WHMCS supports updating in place through the Admin Area (Utilities > Update WHMCS) or by uploading the release package. Back up both your WHMCS files and database before updating.

Utilities → Update WHMCS (in the Admin Area)