CVE-2025-30584: AlphaOmega Captcha CSRF Vulnerability

CVE-2025-30584 Overview

CVE-2025-30584 is a Cross-Site Request Forgery (CSRF) vulnerability in the AlphaOmega Captcha & Anti-Spam Filter WordPress plugin that allows attackers to perform Stored Cross-Site Scripting (XSS) attacks. This chained vulnerability enables malicious actors to trick authenticated administrators into executing unintended actions, ultimately resulting in persistent malicious scripts being stored within the WordPress installation.

Critical Impact

Attackers can chain CSRF and Stored XSS to inject persistent malicious scripts into WordPress sites, potentially compromising administrator sessions, defacing websites, or redirecting users to malicious destinations.

Affected Products

• AlphaOmega Captcha & Anti-Spam Filter plugin version 3.3 and earlier
• WordPress installations using vulnerable versions of alphaomega-captcha-anti-spam
• All WordPress sites with this plugin installed where administrators access untrusted content

Discovery Timeline

• 2025-03-24 - CVE CVE-2025-30584 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-30584

Vulnerability Analysis

This vulnerability represents a dangerous combination of two web application security flaws. The AlphaOmega Captcha & Anti-Spam Filter plugin fails to implement proper CSRF protection on its administrative settings forms, allowing attackers to craft malicious requests that appear to originate from authenticated administrators. The vulnerability is classified under CWE-352 (Cross-Site Request Forgery), indicating that the plugin does not properly validate that requests to modify settings contain a valid nonce or other anti-CSRF token.

When combined with insufficient output encoding on stored settings values, the CSRF vulnerability escalates to a Stored XSS condition. An attacker can inject JavaScript code through plugin settings that will persist in the WordPress database and execute whenever the affected page is rendered, impacting any user who views the compromised content.

Root Cause

The root cause of this vulnerability lies in the plugin's failure to implement two critical security controls: anti-CSRF tokens for administrative form submissions and proper output sanitization/encoding for user-controllable input stored in the database. WordPress provides built-in nonce verification functions (wp_nonce_field() and wp_verify_nonce()) that should be used to protect all state-changing operations, but these appear to be missing or improperly implemented in the affected versions. Additionally, the plugin does not properly sanitize or escape output when displaying stored configuration values, allowing injected scripts to execute in the browser context.

Attack Vector

The attack requires an administrator to visit a malicious website or click a crafted link while authenticated to their WordPress dashboard. The attacker hosts a page containing a hidden form that automatically submits a request to the vulnerable plugin's settings endpoint. Since the browser includes the administrator's session cookies with the request and the plugin lacks CSRF protection, the malicious settings are saved. The stored XSS payload then executes when any user (including the administrator) views pages where the compromised settings are reflected, allowing the attacker to steal session tokens, perform administrative actions, or inject additional malicious content.

Detection Methods for CVE-2025-30584

Indicators of Compromise

• Unexpected changes to AlphaOmega Captcha & Anti-Spam Filter plugin configuration settings
• JavaScript code or <script> tags present in plugin settings stored in the WordPress database
• Administrative sessions being accessed from unfamiliar IP addresses or locations
• Browser-based security tool alerts indicating XSS or script injection attempts

Detection Strategies

• Monitor WordPress wp_options table for changes to alphaomega-captcha-anti-spam related option values containing suspicious HTML or JavaScript
• Implement Web Application Firewall (WAF) rules to detect and block XSS payloads in HTTP request parameters
• Review WordPress admin activity logs for unauthorized plugin configuration changes
• Deploy Content Security Policy (CSP) headers to detect and mitigate script injection attempts

Monitoring Recommendations

• Enable comprehensive WordPress audit logging to track all administrative actions and plugin setting modifications
• Configure real-time alerts for changes to plugin configurations, especially security-related plugins
• Monitor server access logs for unusual patterns of POST requests to plugin administrative endpoints
• Implement browser-based XSS detection mechanisms to identify exploitation attempts

How to Mitigate CVE-2025-30584

Immediate Actions Required

• Update the AlphaOmega Captcha & Anti-Spam Filter plugin to a patched version when available from the vendor
• Review current plugin settings for any injected malicious content and restore clean configurations
• Audit WordPress administrator accounts for any signs of compromise and reset credentials if necessary
• Consider temporarily disabling the plugin until a security patch is released

Patch Information

A security patch addressing CVE-2025-30584 should be obtained from the plugin vendor. WordPress administrators should monitor the Patchstack Vulnerability Advisory for updates on patch availability and apply updates through the WordPress plugin update mechanism as soon as a fixed version is released.

Workarounds

• Implement a Web Application Firewall (WAF) with rules to block CSRF and XSS attack patterns targeting WordPress plugins
• Restrict administrative access to the WordPress dashboard from trusted IP addresses only
• Use browser security extensions that provide CSRF and XSS protection for administrators
• Consider alternative captcha solutions until the vulnerability is patched