Auth0-PHP is a PHP SDK for Auth0 Authentication and Management APIs. In applications built with the Auth0-PHP SDK, the audience validation in access tokens is performed improperly. Without proper validation, affected applications may accept ID tokens as Access tokens. Projects are affected if they use Auth0-PHP SDK versions between v8.0.0 and v8.17.0, or applications using the following SDKs that rely on the Auth0-PHP SDK versions between v8.0.0 and v8.17.0: Auth0/symfony versions between 5.0.0 and 5.5.0, Auth0/laravel-auth0 versions between 7.0.0 and 7.19.0, and/or Auth0/wordpress plugin versions between 5.0.0-BETA0 and 5.4.0. Auth0/Auth0-PHP version 8.18.0 contains a patch for the issue.