CVE-2025-23499: Board Election CSRF Vulnerability

CVE-2025-23499 Overview

CVE-2025-23499 is a Cross-Site Request Forgery (CSRF) vulnerability [CWE-352] in the Pascal Casier board-election WordPress plugin. The flaw chains into a stored Cross-Site Scripting (XSS) condition. It affects all plugin versions up to and including 1.0.1. An attacker who tricks an authenticated administrator into visiting a crafted page can submit forged requests on the victim's behalf. Those requests inject persistent JavaScript payloads into the plugin's stored data. Subsequent visitors then execute the attacker-controlled script in their browser session.

Critical Impact

Successful exploitation enables persistent JavaScript execution in the context of WordPress administrators and site visitors, supporting session theft, account takeover, and further site compromise.

Affected Products

• Pascal Casier Board Election plugin for WordPress, versions through 1.0.1
• WordPress sites with the board-election plugin installed and active
• Any site administrator session interacting with the vulnerable plugin endpoints

Discovery Timeline

• 2025-01-16 - CVE-2025-23499 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-23499

Vulnerability Analysis

The board-election plugin exposes administrative state-changing endpoints without sufficient anti-CSRF protection. The endpoints accept input that is later rendered to other users without proper output encoding. An attacker hosts a malicious page containing a forged form or fetch request targeting the vulnerable plugin action. When an authenticated administrator visits this page, the browser sends the request with valid session cookies attached. The plugin processes the request as legitimate and stores attacker-controlled HTML or JavaScript. The stored payload then executes whenever a user loads the affected plugin view.

Exploitation requires user interaction, but no authentication on the attacker's side. The scope is changed because injected scripts execute in the WordPress origin and can affect users beyond the initial victim.

Root Cause

The root cause is a missing or improperly validated CSRF token on plugin request handlers, compounded by missing output sanitization. WordPress provides wp_nonce_field() and check_admin_referer() primitives that the plugin does not enforce on the affected actions. Stored input is rendered without functions such as esc_html() or esc_attr(), allowing HTML and <script> content to persist verbatim.

Attack Vector

The attack vector is network-based and requires user interaction. The attacker delivers a phishing link or embeds a hidden form on a third-party site. The victim must hold an authenticated session on the target WordPress instance. The vulnerability mechanism is described in the Patchstack WordPress Vulnerability Report.

Detection Methods for CVE-2025-23499

Indicators of Compromise

• Unexpected <script>, onerror, or onload attributes stored in board-election plugin database tables or WordPress options.
• Administrator account activity originating from referrers outside the WordPress admin domain.
• New or modified plugin entries created shortly after an admin visited an external link.
• Outbound requests from visitor browsers to unfamiliar domains after loading election-related pages.

Detection Strategies

• Audit WordPress database tables created by the board-election plugin for HTML or JavaScript content in text fields.
• Review web server access logs for POST requests to plugin admin endpoints that lack the _wpnonce parameter.
• Inspect rendered pages with a headless browser to detect injected script execution from plugin output.
• Correlate admin POST actions with Referer headers pointing to external untrusted origins.

Monitoring Recommendations

• Enable WordPress activity logging for plugin setting and content changes attributable to administrator sessions.
• Deploy a Web Application Firewall (WAF) rule set that flags POST requests to plugin endpoints missing nonce parameters.
• Monitor Content Security Policy (CSP) violation reports for inline script execution on pages rendered by the plugin.
• Alert on creation of administrator-authored content containing HTML event handlers or <script> tags.

How to Mitigate CVE-2025-23499

Immediate Actions Required

• Deactivate and remove the board-election plugin until a patched version above 1.0.1 is published by the maintainer.
• Force a password reset for all WordPress administrator accounts and invalidate active sessions.
• Review plugin-managed data and purge any entries containing script tags or HTML event handlers.
• Restrict administrator browsing on hosts that manage the WordPress site to limit cross-site request exposure.

Patch Information

No fixed version is identified in the advisory. The vulnerability affects Board Election versions through 1.0.1. Monitor the Patchstack advisory and the plugin's WordPress.org page for a vendor release that adds nonce verification and output escaping.

Workarounds

• Apply a virtual patch through a WAF to require a valid _wpnonce value on requests to plugin admin endpoints.
• Enforce a strict Content Security Policy that disallows inline scripts on pages rendered by the plugin.
• Use a browser isolation profile or a dedicated browser for WordPress administration to break CSRF chains.
• Limit administrator role assignment to the minimum number of users while the plugin remains unpatched.

# Example WAF rule (ModSecurity) to block plugin admin POSTs missing a nonce
SecRule REQUEST_METHOD "@streq POST" \
  "chain,id:1002349,phase:2,deny,status:403,msg:'CVE-2025-23499 board-election CSRF guard'"
  SecRule REQUEST_URI "@contains /wp-admin/admin.php?page=board-election" \
    "chain"
    SecRule &ARGS:_wpnonce "@eq 0"