CVE-2025-9629 Overview
CVE-2025-9629 is a Cross-Site Request Forgery (CSRF) vulnerability in the USS Upyun plugin for WordPress. The flaw affects all versions up to and including 1.5.0. The root cause is missing or incorrect nonce validation on the uss_setting_page function when processing the uss_set form type.
Attackers can trick a site administrator into clicking a crafted link to modify Upyun cloud storage settings. Affected parameters include bucket name, operator credentials, upload paths, and image processing parameters. The vulnerability is tracked under [CWE-352].
Critical Impact
Unauthenticated attackers can alter cloud storage configuration on a WordPress site by tricking an administrator into visiting a malicious page, redirecting uploads or exposing media to attacker-controlled Upyun buckets.
Affected Products
- USS Upyun plugin for WordPress — all versions up to and including 1.5.0
- WordPress sites using the USS Upyun plugin for Upyun cloud storage integration
- Fixed in USS Upyun plugin version 1.5.1
Discovery Timeline
- 2025-09-17 - CVE-2025-9629 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-9629
Vulnerability Analysis
The USS Upyun plugin exposes a settings handler, uss_setting_page, that processes the uss_set form submission. This handler updates the plugin's cloud storage configuration but does not verify a valid WordPress nonce before applying changes.
Without nonce validation, WordPress cannot confirm that the settings request originated from an authenticated administrator's own browser session. An attacker can therefore construct an HTML form or link that submits arbitrary settings values to the vulnerable endpoint. When a logged-in administrator visits the attacker's page, the browser sends the request with valid session cookies, and the plugin accepts the change.
Successful exploitation lets the attacker overwrite the Upyun bucket name, operator credentials, upload paths, and image processing parameters. This can redirect subsequent media uploads to an attacker-controlled bucket or break integrity of asset delivery on the site.
Root Cause
The root cause is missing or incorrect nonce validation in the uss_setting_page function when handling the uss_set form type. WordPress provides wp_verify_nonce and check_admin_referer primitives for exactly this scenario, but the affected code path does not enforce them. Relevant code locations are documented in the WordPress Plugin Code Snippet at line 493 and line 499.
Attack Vector
Exploitation requires user interaction from an authenticated WordPress administrator, such as clicking a link or loading a page that hosts a hidden auto-submitting form. No prior authentication or privileges are required for the attacker. The request executes against the WordPress admin endpoint under the administrator's session, applying the attacker-chosen values to the plugin configuration.
See the Wordfence Vulnerability Report for the full advisory. No verified exploit code is available at this time.
Detection Methods for CVE-2025-9629
Indicators of Compromise
- Unexpected changes to Upyun plugin settings, including bucket name, operator, operator password, or upload path values.
- New or modified media uploads pointing to an unfamiliar Upyun bucket or CDN hostname.
- Administrator-initiated POST requests to the plugin settings endpoint with an HTTP Referer header pointing to an external domain.
- Audit log entries showing option updates for USS Upyun keys without a corresponding admin session on the WordPress dashboard.
Detection Strategies
- Compare current plugin settings against a known-good baseline of Upyun bucket, operator, and path values.
- Alert on modifications to WordPress wp_options rows tied to the USS Upyun plugin.
- Review web server access logs for external referers on requests to /wp-admin/ handlers that update plugin settings.
Monitoring Recommendations
- Enable WordPress activity logging to record option changes and administrator actions.
- Monitor outbound traffic from the site to Upyun API endpoints for unexpected bucket destinations.
- Track plugin version inventory across managed WordPress sites to identify hosts still on 1.5.0 or earlier.
How to Mitigate CVE-2025-9629
Immediate Actions Required
- Update the USS Upyun plugin to version 1.5.1 or later on all WordPress sites.
- Review current Upyun plugin settings and restore the correct bucket, operator credentials, and upload path values if any tampering is suspected.
- Rotate Upyun operator passwords used by the plugin if administrator sessions may have been targeted.
Patch Information
The vendor addressed the issue in USS Upyun 1.5.1. The corrected code is visible in the WordPress Plugin Code Snippet for tag 1.5.1, which introduces the required nonce verification on the uss_set form path.
Workarounds
- Deactivate the USS Upyun plugin until it can be upgraded to 1.5.1.
- Require administrators to log out of the WordPress dashboard when not actively managing the site to reduce CSRF exposure.
- Restrict /wp-admin/ access by source IP address using web server or WAF rules where feasible.
- Enforce browser protections such as SameSite=Lax or Strict session cookies on the WordPress site.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
