CVE-2025-31383: FrescoChat CSRF & Stored XSS Vulnerability

CVE-2025-31383 Overview

CVE-2025-31383 is a Cross-Site Request Forgery (CSRF) vulnerability in the sodena FrescoChat Live Chat WordPress plugin (flexytalk-widget) that enables Stored Cross-Site Scripting (XSS) attacks. This chained vulnerability allows attackers to trick authenticated administrators into unknowingly submitting malicious requests that inject persistent JavaScript code into the plugin's settings, which then executes in the browsers of subsequent visitors.

Critical Impact

Attackers can leverage CSRF to inject persistent malicious scripts into WordPress sites using FrescoChat Live Chat, potentially compromising site administrators and visitors through session hijacking, credential theft, or malware distribution.

Affected Products

• FrescoChat Live Chat (flexytalk-widget) versions up to and including 3.2.6
• WordPress installations with the vulnerable plugin active

Discovery Timeline

• 2025-04-09 - CVE-2025-31383 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-31383

Vulnerability Analysis

This vulnerability combines two distinct attack vectors into a powerful exploitation chain. The CSRF component (CWE-352) stems from missing or improper verification of nonce tokens in the plugin's administrative settings forms. Without proper anti-CSRF protections, the plugin fails to validate that settings update requests originate from legitimate administrator sessions.

The secondary Stored XSS component arises because the plugin does not adequately sanitize or escape user-supplied input before storing it in the database and rendering it on pages. When an attacker successfully exploits the CSRF vulnerability to inject malicious JavaScript code into plugin settings, that code persists in the WordPress database and executes every time the affected pages are loaded.

This attack requires user interaction—specifically, an authenticated administrator must visit a malicious page or click a crafted link while logged into WordPress. The network-accessible nature of this vulnerability means attackers can host exploit pages anywhere on the internet and use social engineering to lure administrators.

Root Cause

The root cause is twofold: first, the plugin's settings update handlers lack proper CSRF token validation (nonce verification), allowing forged cross-origin requests to be processed as legitimate. Second, insufficient input sanitization and output encoding permit the storage and execution of arbitrary JavaScript payloads within plugin configuration fields.

Attack Vector

The attack follows a multi-stage exploitation path:

1. The attacker crafts a malicious HTML page containing a hidden form or JavaScript that targets the vulnerable plugin's settings endpoint
2. The form includes malicious XSS payloads in configurable fields such as chat widget settings, custom CSS, or JavaScript injection points
3. When an authenticated WordPress administrator visits the attacker's page, the browser automatically submits the forged request using the administrator's active session
4. The plugin processes the request without CSRF validation and stores the malicious payload
5. The stored XSS payload executes whenever users or administrators view pages where the chat widget is rendered

The exploitation mechanism involves crafting a page that automatically submits a POST request to the plugin's settings endpoint with malicious JavaScript in configuration fields. Due to the lack of CSRF protection, the plugin accepts and saves these settings when an authenticated admin visits the attacker-controlled page. For detailed technical information, see the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-31383

Indicators of Compromise

• Unexpected modifications to FrescoChat Live Chat plugin settings without administrator action
• Presence of <script> tags, event handlers (e.g., onerror, onload), or JavaScript URIs in plugin configuration fields
• Browser console errors or unexpected network requests when loading pages with the chat widget
• Administrator session cookies being exfiltrated or unusual authentication activity

Detection Strategies

• Review WordPress database entries related to the flexytalk-widget plugin for suspicious JavaScript or HTML content
• Monitor HTTP logs for POST requests to plugin settings endpoints from external referrers
• Implement Web Application Firewall (WAF) rules to detect CSRF patterns and XSS payloads targeting WordPress admin endpoints
• Conduct periodic audits of plugin configuration values for unauthorized changes

Monitoring Recommendations

• Enable WordPress audit logging to track all plugin settings modifications with timestamp and user attribution
• Configure SentinelOne to monitor for anomalous browser behavior and script execution patterns on WordPress-hosted infrastructure
• Set up alerts for administrative actions performed outside of normal operational hours
• Monitor for outbound connections to suspicious domains from WordPress servers

How to Mitigate CVE-2025-31383

Immediate Actions Required

• Update FrescoChat Live Chat (flexytalk-widget) to a patched version if available from the vendor
• If no patch is available, consider temporarily deactivating and removing the plugin until a fix is released
• Review and clean any existing plugin settings for malicious JavaScript content
• Advise WordPress administrators to avoid clicking links or visiting untrusted websites while logged into the admin panel

Patch Information

The vulnerability affects FrescoChat Live Chat versions through 3.2.6. Organizations should check the WordPress plugin repository or contact sodena directly for information about updated versions that address this CSRF to Stored XSS vulnerability chain. Monitor the Patchstack Vulnerability Report for patch availability updates.

Workarounds

• Implement server-level CSRF protection through a Web Application Firewall (WAF) with rules targeting state-changing requests without valid nonce tokens
• Restrict access to WordPress admin panels by IP address or VPN to limit exposure to CSRF attacks
• Use Content Security Policy (CSP) headers to mitigate the impact of any stored XSS payloads that may have been injected
• Consider using a WordPress security plugin that provides additional CSRF and XSS protection layers

# Example: Add Content-Security-Policy header in Apache .htaccess
# Place in WordPress root directory
Header set Content-Security-Policy "script-src 'self' 'unsafe-inline' https://trusted-cdn.example.com; object-src 'none';"

# Example: Restrict wp-admin access by IP in .htaccess
<Files wp-login.php>
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
</Files>