CVE-2025-23886: Annie WordPress Plugin Stored XSS Vulnerability

CVE-2025-23886 Overview

CVE-2025-23886 is a stored Cross-Site Scripting (XSS) vulnerability in the Chris Roberts Annie WordPress plugin. The flaw affects all versions of Annie up to and including 2.1.1. It stems from Improper Neutralization of Input During Web Page Generation [CWE-79], allowing an authenticated attacker with low privileges to inject persistent JavaScript into pages rendered by the plugin. When another user views the affected page, the injected script executes in their browser session.

Critical Impact

An authenticated attacker can inject stored JavaScript that executes in the browsers of site visitors and administrators, enabling session theft, forced actions, and content defacement.

Affected Products

• Chris Roberts Annie plugin for WordPress
• All versions from initial release through 2.1.1
• WordPress sites with the vulnerable plugin activated

Discovery Timeline

• 2025-01-16 - CVE-2025-23886 published to the National Vulnerability Database
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-23886

Vulnerability Analysis

The Annie plugin fails to properly sanitize or encode user-supplied input before rendering it in HTML output. An authenticated user with contributor-level or similar low privileges can submit crafted input containing HTML or JavaScript payloads. The plugin stores this input and later reflects it into web pages without adequate encoding.

Because the payload persists in the WordPress database, every subsequent visitor to the affected page triggers script execution. The vulnerability crosses a scope boundary, meaning the injected script can act against users with higher privileges than the attacker. Successful exploitation requires the victim to interact with the page containing the payload.

Root Cause

The root cause is missing or insufficient output encoding on user-controlled data. The plugin does not apply WordPress sanitization functions such as esc_html(), esc_attr(), or wp_kses() before echoing stored values into the response. This violates the standard WordPress secure development pattern of sanitizing on input and escaping on output.

Attack Vector

Exploitation follows a typical stored XSS pattern. The attacker authenticates to the WordPress instance with a low-privilege account. The attacker submits a payload containing a <script> tag or an event handler such as onerror through an input field processed by the Annie plugin. The payload is persisted server-side.

When an administrator or other user loads the page rendering the stored value, the browser parses and executes the attacker's JavaScript in the context of the site origin. This grants the attacker access to session cookies, the WordPress REST API under the victim's identity, and any actions the victim can perform in the admin interface.

See the Patchstack XSS Vulnerability Report for advisory details.

Detection Methods for CVE-2025-23886

Indicators of Compromise

• Unexpected <script> tags, javascript: URIs, or inline event handlers (onerror, onload, onclick) stored in WordPress wp_posts or plugin-specific tables
• Administrator sessions issuing unexpected REST API calls to /wp-json/wp/v2/users or plugin endpoints
• New administrator accounts, altered user roles, or modified plugin settings without a corresponding audit trail
• Outbound HTTP requests from browser sessions to unfamiliar domains after loading Annie-rendered pages

Detection Strategies

• Query the WordPress database for stored HTML or script patterns in fields managed by the Annie plugin
• Deploy a web application firewall rule matching XSS payloads on POST requests to Annie plugin endpoints
• Review web server access logs for POST requests from low-privilege accounts followed by administrator page loads triggering script execution
• Enable Content Security Policy (CSP) reporting to capture blocked inline script executions on plugin-rendered pages

Monitoring Recommendations

• Alert on new administrator or editor account creation events in WordPress audit logs
• Monitor plugin file integrity and configuration changes
• Track authentication anomalies such as session token reuse across geographically distant IP addresses
• Correlate browser telemetry with WordPress activity to identify script-driven privilege escalation

How to Mitigate CVE-2025-23886

Immediate Actions Required

• Deactivate the Annie plugin on all WordPress sites until a patched version is confirmed
• Audit user accounts and remove any unauthorized administrator or editor roles
• Rotate authentication cookies, application passwords, and API keys for any users who accessed Annie-rendered pages
• Review the WordPress database for persisted XSS payloads and remove malicious content

Patch Information

No fixed version is identified in the advisory at the time of publication. All versions up to and including 2.1.1 are affected. Site operators should monitor the Patchstack advisory and the plugin repository for an updated release addressing CVE-2025-23886.

Workarounds

• Uninstall the Annie plugin if it is not business-critical
• Restrict contributor and author account creation and require multi-factor authentication for all authenticated users
• Enforce a strict Content Security Policy that blocks inline script execution on WordPress pages
• Place the WordPress instance behind a web application firewall configured with XSS filtering rules

# Example Content Security Policy header for WordPress (Apache)
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'"