What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
USS Upyun versions 1.5.0 and earlier are vulnerable to cross-site request forgery (CSRF) attacks. An attacker can craft a malicious webpage that, when visited by a logged-in site administrator, performs unwanted actions on the site without the admin's knowledge or consent. The attack requires the victim to visit the attacker's page while authenticated.
What an attacker can do
03Attacker Capabilities
Perform unwanted actions on the site by tricking an authenticated admin into visiting a malicious webpage.
Potential impact on your site
04Site Impact
An attacker can modify site settings or data by exploiting an admin's browser session without their awareness.
Conditions required to exploit
05Prerequisites
Victim must be logged in and visit an attacker-controlled page; no special privileges required.
Key dates
06Disclosure timeline
September 17, 2025
CVE published
April 8, 2026
Record updated
