Impact In applications built with the Auth0 PHP SDK, cookies are encrypted with insufficient entropy, which may result in threat actors brute-forcing the encryption key and forging session cookies.

Am I Affected? Consumers are affected if their application meets the following preconditions: - Their application is using the Auth0-PHP SDK, versions between 8.0.0 and 8.18.0 - Their application is using the Auth0-PHP SDK, or the following SDKs that rely on the Auth0-PHP SDK: - Auth0/symfony, - Auth0/laravel0-auth0, or - Auth0/wordpress

Resolution Upgrade Auth0/Auth0-PHP to version 8.19.0 or greater.

Description 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. Affected product and versions Projects are affected if they meet the following preconditions:

- Applications using the 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: - a. Auth0/symfony, - b. Auth0/laravel-auth0, - c. Auth0/wordpress.

Resolution Upgrade Auth0/Auth0-PHP to version 8.18.0 or greater.

Acknowledgement Okta would like to thank Jafar Sadiq (iaf4r) for their discovery and responsible disclosure.