CVE-2026-57406: FundEngine Authorization Bypass Vulnerability

CVE-2026-57406 Overview

CVE-2026-57406 is a missing authorization vulnerability in the Roxnor FundEngine WordPress plugin (wp-fundraising-donation). The flaw affects all versions up to and including 1.7.6 and stems from incorrectly configured access control security levels [CWE-862]. An unauthenticated attacker can reach protected plugin functionality over the network without any user interaction. Successful exploitation allows attackers to modify data or degrade availability of fundraising features on affected WordPress sites.

Critical Impact
Unauthenticated network-based attackers can invoke restricted plugin actions, leading to limited integrity and availability impact on WordPress installations running FundEngine <= 1.7.6.

Affected Products

Roxnor FundEngine (wp-fundraising-donation) WordPress plugin, versions up to and including 1.7.6
WordPress sites with the FundEngine donation plugin activated
Any downstream fundraising site or template bundling the vulnerable plugin

Discovery Timeline

2026-07-13 - CVE-2026-57406 published to NVD
2026-07-13 - Last updated in NVD database

Technical Details for CVE-2026-57406

Vulnerability Analysis

The FundEngine plugin exposes plugin actions that fail to verify the caller's privilege level before executing sensitive operations. WordPress plugins typically enforce access control using current_user_can() capability checks and nonce validation on AJAX or admin-post handlers. In FundEngine <= 1.7.6, one or more endpoints omit these checks, so any HTTP client can invoke them.

The attack requires only network access and no authentication. Because the impacted actions are exposed through standard WordPress request handlers, the attack surface is reachable from the public internet on any site that has the plugin installed. Integrity and availability of donation-related data can be affected, while confidentiality is not directly impacted per the assigned vector.

Root Cause

The root cause is a missing authorization check [CWE-862] on plugin request handlers. The code path executes privileged fundraising logic without first confirming the requester holds the required WordPress capability or nonce. This is a classic Broken Access Control pattern, where authentication and role checks are assumed but not enforced at the handler entry point.

Attack Vector

An attacker sends crafted HTTP requests directly to the vulnerable plugin endpoints exposed by WordPress. Because no authentication is required, exploitation can be automated at scale against sites indexed by search engines or fingerprinted through plugin asset paths. The attacker manipulates request parameters targeting the unprotected action to alter fundraising records or trigger state changes that impair plugin availability. Refer to the Patchstack Vulnerability Report for handler-level technical details.

Detection Methods for CVE-2026-57406

Indicators of Compromise

Unauthenticated POST or GET requests to FundEngine plugin handlers under /wp-admin/admin-ajax.php or /wp-admin/admin-post.php with FundEngine action names
Unexpected modifications to donation records, campaign settings, or plugin options without a corresponding authenticated admin session
Requests to plugin endpoints originating from IPs that have no prior authenticated session cookies

Detection Strategies

Inspect WordPress access logs for requests to FundEngine action= parameters lacking a valid _wpnonce value
Compare wp_options and plugin database tables against known-good snapshots to identify unauthorized changes
Alert on anomalous write activity to donation-related tables outside of normal admin working hours

Monitoring Recommendations

Enable WordPress audit logging with a plugin that records administrative actions and REST/AJAX endpoint calls
Forward web server and WordPress logs to a centralized SIEM to correlate scanning and exploitation attempts
Monitor Patchstack, WPScan, and NVD feeds for updates to CVE-2026-57406 and new indicators

How to Mitigate CVE-2026-57406

Immediate Actions Required

Update the FundEngine (wp-fundraising-donation) plugin to a version later than 1.7.6 as soon as the vendor releases a fix
If no patched version is available, deactivate and remove the plugin from production WordPress sites
Review donation and campaign data for unauthorized modifications made prior to remediation

Patch Information

At the time of publication, the vulnerability affects FundEngine <= 1.7.6 with no fixed version listed in the referenced advisory. Monitor the Patchstack Vulnerability Report and the plugin's WordPress.org page for a patched release.

Workarounds

Restrict access to /wp-admin/admin-ajax.php and /wp-admin/admin-post.php FundEngine actions via a Web Application Firewall (WAF) rule that requires an authenticated session cookie
Apply IP allowlisting to /wp-admin/ for administrative networks where feasible
Disable the plugin on sites that do not actively use fundraising features until a patched release is available

bash

# Example: block unauthenticated requests to FundEngine actions at the web server
# nginx snippet
location = /wp-admin/admin-ajax.php {
    if ($arg_action ~* "^(fundengine|wpfd|roxnor)_") {
        if ($http_cookie !~* "wordpress_logged_in_") {
            return 403;
        }
    }
    include fastcgi_params;
    fastcgi_pass php_upstream;
}