CVE-2025-47500: Stackable Gutenberg Blocks XSS Flaw

CVE-2025-47500 Overview

CVE-2025-47500 is a Stored Cross-Site Scripting (XSS) vulnerability affecting the Stackable – Page Builder Gutenberg Blocks plugin for WordPress, developed by Benjamin Intal. This vulnerability arises from improper neutralization of input during web page generation (CWE-79), allowing attackers to inject and persist malicious scripts within the WordPress environment.

The Stackable plugin is a popular Gutenberg block builder that extends WordPress's native editor with additional design and layout capabilities. Due to insufficient input sanitization, authenticated attackers can inject malicious JavaScript code that executes in the browsers of users who view affected pages.

Critical Impact

Authenticated attackers can inject persistent malicious scripts that execute in victim browsers, potentially leading to session hijacking, credential theft, and site defacement.

Affected Products

• Stackable – Page Builder Gutenberg Blocks plugin versions up to and including 3.19.5
• WordPress installations running vulnerable versions of the Stackable plugin
• All websites using stackable-ultimate-gutenberg-blocks with affected versions

Discovery Timeline

• 2026-01-22 - CVE-2025-47500 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2025-47500

Vulnerability Analysis

This Stored XSS vulnerability exists within the Stackable Gutenberg blocks plugin, which provides enhanced page building capabilities for WordPress sites. The vulnerability stems from inadequate sanitization of user-supplied input that gets processed and rendered within the Gutenberg block editor and front-end output.

When users interact with Stackable blocks, certain input fields fail to properly neutralize special characters and script elements before storing them in the database. This allows attackers with the ability to create or modify content (such as Contributors, Authors, or higher-privileged users) to embed malicious JavaScript that persists within WordPress pages or posts.

The stored nature of this XSS vulnerability makes it particularly dangerous, as the malicious payload is saved to the database and executes every time a victim views the compromised content, without requiring any additional interaction from the attacker.

Root Cause

The root cause is improper neutralization of input during web page generation. The Stackable plugin fails to adequately sanitize and escape user-controlled input within certain Gutenberg block attributes before rendering them in the browser. This allows attackers to inject script tags or event handlers that bypass insufficient filtering mechanisms.

Attack Vector

The attack requires an authenticated user with content creation privileges (such as Contributor, Author, Editor, or Administrator roles) to craft a malicious Stackable block containing JavaScript payloads. The attack flow typically involves:

1. An authenticated attacker accesses the WordPress editor with Stackable blocks enabled
2. The attacker creates or modifies a page/post using vulnerable Stackable block fields
3. Malicious JavaScript is injected into block attributes that lack proper sanitization
4. The payload is stored in the WordPress database
5. When any user (including administrators) views the affected page, the malicious script executes in their browser context

The vulnerability does not require user interaction beyond normal page viewing, making it an effective vector for privilege escalation, session hijacking, or website defacement attacks.

Detection Methods for CVE-2025-47500

Indicators of Compromise

• Unexpected JavaScript code present in Stackable block attributes within the wp_posts table
• Anomalous script tags or event handlers within serialized Gutenberg block content
• User reports of unexpected browser behavior or redirects when viewing specific pages
• Suspicious modifications to pages or posts by lower-privileged users

Detection Strategies

• Review WordPress database content for script injection patterns within Stackable block metadata
• Monitor WordPress audit logs for unusual content modifications by Contributor or Author role users
• Implement Web Application Firewall (WAF) rules to detect XSS payload patterns in POST requests to WordPress editor endpoints
• Utilize SentinelOne's browser-based threat detection to identify malicious script execution

Monitoring Recommendations

• Enable comprehensive logging for all content creation and modification activities in WordPress
• Configure alerts for JavaScript or HTML injection patterns in post content
• Monitor for unusual network requests originating from client browsers after page loads
• Implement Content Security Policy (CSP) headers to mitigate script execution from unauthorized sources

How to Mitigate CVE-2025-47500

Immediate Actions Required

• Update the Stackable plugin to the latest version beyond 3.19.5 that contains the security fix
• Audit existing WordPress content for potential XSS payloads injected via Stackable blocks
• Review user roles and restrict content creation privileges to trusted users only
• Implement a Web Application Firewall with XSS protection rules

Patch Information

The vulnerability affects Stackable versions from the initial release through 3.19.5. Website administrators should update to the latest patched version available through the WordPress plugin repository. Detailed vulnerability information is available through the Patchstack Vulnerability Report.

Workarounds

• Temporarily disable the Stackable plugin until a patched version is installed
• Restrict content editing capabilities to Administrator accounts only
• Implement strict Content Security Policy headers to prevent inline script execution
• Use security plugins to scan and sanitize existing content for XSS payloads

# WordPress CLI command to update Stackable plugin
wp plugin update stackable-ultimate-gutenberg-blocks

# Verify current plugin version
wp plugin list --name=stackable-ultimate-gutenberg-blocks --fields=name,version,status

# Temporarily deactivate plugin if update is not immediately available
wp plugin deactivate stackable-ultimate-gutenberg-blocks