CVE-2024-8428 Overview
CVE-2024-8428 is a privilege escalation vulnerability in the ForumWP – Forum & Discussion Board Plugin for WordPress. The flaw affects all versions up to and including 2.0.2 and stems from an Insecure Direct Object Reference (IDOR) in the submit_form_handler function. The handler fails to validate the user-controlled user_id parameter, allowing authenticated attackers with subscriber-level access to modify the email address of any account, including administrators. Attackers can then trigger a password reset against the changed email and take over the administrative account.
Critical Impact
Any authenticated subscriber can hijack administrator accounts, leading to full WordPress site compromise.
Affected Products
- Ultimate Member ForumWP Plugin for WordPress — versions <= 2.0.2
- Fixed in ForumWP 2.1.0
- WordPress installations with ForumWP active and open user registration
Discovery Timeline
- 2024-09-06 - CVE-2024-8428 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-8428
Vulnerability Analysis
The vulnerability is classified as an Insecure Direct Object Reference [CWE-639]. The submit_form_handler function inside class-actions-listener.php processes profile-update form submissions but trusts the user_id value supplied by the client. Because the plugin does not verify that the submitted user_id matches the currently authenticated user, an attacker can substitute another account's identifier and update its profile fields.
The email address field is the highest-impact target. Once an attacker rewrites an administrator's email address, they can request a standard WordPress password reset. The reset link is sent to the attacker-controlled email, yielding administrator access and full control of the site, including plugin installation, theme editing, and PHP code execution.
Authentication is required, but WordPress sites running ForumWP typically allow open registration at the subscriber tier, which lowers the barrier to exploitation significantly.
Root Cause
The root cause is missing authorization on a user-controlled object identifier. The handler accepts user_id from the request body and passes it into WordPress user-update routines without checking current_user_can() against that specific identifier or comparing it to get_current_user_id(). This design pattern violates least-privilege enforcement on server-side object access.
Attack Vector
Exploitation is performed remotely over the network against the ForumWP AJAX or form-processing endpoint. An attacker registers a subscriber account, submits a profile-edit request while replacing the user_id parameter with the administrator's numeric ID (commonly 1), and swaps the user_email value for an attacker-controlled address. The attacker then navigates to wp-login.php?action=lostpassword, requests a reset for the compromised admin account, and receives the reset token by email. See the Wordfence Vulnerability Report and the ForumWP source in class-actions-listener.php for the vulnerable code path.
Detection Methods for CVE-2024-8428
Indicators of Compromise
- Unexpected changes to the user_email field on administrator accounts in the wp_users table.
- Password reset requests for administrator accounts originating shortly after profile submissions from low-privilege sessions.
- POST requests to ForumWP form endpoints containing user_id values that do not match the authenticated session's user ID.
- New administrator logins from unfamiliar IP addresses following a subscriber account registration.
Detection Strategies
- Audit WordPress access logs for POST requests to ForumWP action handlers where the submitting user has subscriber-level privileges but the user_id payload references another account.
- Monitor the WordPress user_email column for changes on privileged accounts and alert on any modification that does not correspond to an administrator session.
- Correlate password reset email events with recent profile-form submissions from non-privileged users.
Monitoring Recommendations
- Enable WordPress audit logging for user profile changes, role assignments, and password reset activity.
- Forward web server and WordPress application logs to a centralized SIEM for cross-event correlation.
- Alert on administrator account logins that follow email address changes within a short time window.
How to Mitigate CVE-2024-8428
Immediate Actions Required
- Update ForumWP to version 2.1.0 or later on all WordPress installations.
- Review all administrator accounts for unauthorized email address changes and reset credentials where tampering is suspected.
- Disable open user registration temporarily if patching cannot be performed immediately.
- Enforce multi-factor authentication on all administrator accounts to blunt password-reset takeover.
Patch Information
The vendor addressed the vulnerability in ForumWP 2.1.0. The fix adds validation that the submitted user_id matches the authenticated user before applying profile updates. Review the upstream fix in changeset 3161123.
Workarounds
- Deactivate the ForumWP plugin until the site can be upgraded to 2.1.0.
- Restrict access to ForumWP form-handler endpoints via a Web Application Firewall (WAF) rule that inspects user_id values against the session owner.
- Limit new user registrations and require administrator approval for subscriber accounts to reduce the pool of authenticated attackers.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
