Medium · published September 17, 2025
The USS Upyun plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.5.0. This is due to missing or incorrect nonce validation on the uss_setting_page function when processing the uss_set form type. This makes it possible for unauthenticated attackers to modify critical Upyun cloud storage settings including bucket name, operator credentials, upload paths, and image processing parameters via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.