CVE-2025-39533 Overview
CVE-2025-39533 is a missing authorization vulnerability [CWE-862] in the Starfish Review Generation & Marketing plugin for WordPress, developed by Starfish Reviews. The flaw allows an authenticated attacker with low privileges to update arbitrary WordPress options, leading to privilege escalation. All plugin versions up to and including 3.1.19 are affected.
The vulnerability enables a subscriber-level account to elevate to administrator by modifying sensitive WordPress configuration options. Successful exploitation grants complete control of the affected WordPress site.
Critical Impact
Authenticated attackers with minimal privileges can escalate to administrator by abusing missing capability checks to write arbitrary WordPress options.
Affected Products
- Starfish Review Generation & Marketing plugin for WordPress
- All versions from initial release through 3.1.19
- WordPress sites running the starfish-reviews plugin
Discovery Timeline
- 2025-04-17 - CVE-2025-39533 published to NVD
- 2026-04-23 - Last updated in NVD database
Technical Details for CVE-2025-39533
Vulnerability Analysis
The Starfish Review Generation & Marketing plugin exposes one or more action handlers that update WordPress options without verifying the caller's capabilities. WordPress options control site-wide configuration, including the default user role assigned to new registrations and administrative behavior.
An attacker authenticated as a low-privileged user, such as a subscriber, can invoke the vulnerable endpoint and write arbitrary values to options like default_role or users_can_register. By setting default_role to administrator and enabling open registration, the attacker creates a new administrator account and takes over the site.
The vulnerability requires network access and low privileges, with no user interaction. It impacts confidentiality, integrity, and availability of the WordPress installation.
Root Cause
The root cause is missing authorization [CWE-862] in plugin handlers that process option-update requests. The code does not call current_user_can() or equivalent capability checks before writing to the WordPress options table. Nonce validation alone, if present, does not restrict the action to privileged users.
Attack Vector
An attacker first obtains any authenticated session on the target WordPress site, typically through self-registration on sites that allow it or through credential reuse. The attacker then sends a crafted HTTP request to the vulnerable plugin endpoint, targeting WordPress options that govern user creation and role assignment.
After modifying default_role to administrator and enabling user registration, the attacker registers a new account that is automatically granted administrative privileges. See the Patchstack WordPress Vulnerability Report for additional technical context.
Detection Methods for CVE-2025-39533
Indicators of Compromise
- Unexpected administrator accounts in wp_users and wp_usermeta tables that did not exist prior to the suspected exploitation window.
- Modifications to the default_role or users_can_register options in wp_options outside of normal administrator activity.
- New plugin or theme installations, or modifications to existing files, performed by recently created user accounts.
- HTTP POST requests to Starfish Reviews plugin endpoints originating from subscriber-level sessions.
Detection Strategies
- Monitor web server access logs for POST requests targeting admin-ajax.php or REST endpoints associated with the starfish-reviews plugin from non-administrator users.
- Audit the wp_options table for unauthorized changes to administrative settings, comparing against known-good baselines.
- Enable WordPress audit logging plugins to record option updates, role changes, and new user creation events.
Monitoring Recommendations
- Alert on any change to the default_role option, which should rarely change in production environments.
- Track creation of new administrator accounts and correlate with the originating IP and session.
- Review plugin inventory regularly to confirm the Starfish Reviews plugin is patched or removed.
How to Mitigate CVE-2025-39533
Immediate Actions Required
- Identify all WordPress sites running the Starfish Review Generation & Marketing plugin at version 3.1.19 or earlier.
- Disable or uninstall the plugin until a patched version is installed if site functionality permits.
- Set users_can_register to 0 and confirm default_role is set to subscriber to limit registration abuse.
- Audit administrator accounts and revoke any unrecognized privileged users.
Patch Information
At the time of the NVD entry, the advisory indicates affected versions from n/a through 3.1.19. Site administrators should consult the Patchstack WordPress Vulnerability Report and the plugin's WordPress.org page for the latest fixed version and upgrade immediately.
Workarounds
- Restrict access to wp-admin and admin-ajax.php by IP address using web server rules where feasible.
- Deploy a web application firewall rule to block requests to vulnerable Starfish Reviews endpoints from non-administrator users.
- Disable user self-registration on the WordPress site to remove the low-privileged foothold required for exploitation.
- Remove the plugin entirely if it is not in active use.
# Configuration example: disable open registration via WP-CLI
wp option update users_can_register 0
wp option update default_role subscriber
wp plugin deactivate starfish-reviews
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
