CVE-2025-31574: Custom Content Scrollbar XSS Vulnerability

CVE-2025-31574 Overview

CVE-2025-31574 is a stored cross-site scripting (XSS) vulnerability in the SoftHopper Custom Content Scrollbar plugin for WordPress. The flaw stems from improper neutralization of user-supplied input during web page generation [CWE-79]. Authenticated attackers with low privileges can inject malicious scripts that persist in the plugin's stored data. The payload executes in the browsers of users who view affected pages. The issue affects all versions of Custom Content Scrollbar up to and including 1.3.

Critical Impact

Attackers can inject persistent JavaScript that runs in visitor and administrator browsers, enabling session theft, defacement, and privilege escalation through administrative session hijacking.

Affected Products

• SoftHopper Custom Content Scrollbar WordPress plugin, versions up to and including 1.3
• WordPress sites with the custom-content-scrollbar plugin installed and activated
• Any WordPress deployment allowing contributor-level or higher accounts on vulnerable plugin versions

Discovery Timeline

• 2025-03-31 - CVE-2025-31574 published to the National Vulnerability Database
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-31574

Vulnerability Analysis

The Custom Content Scrollbar plugin fails to sanitize and escape user-controlled input before rendering it inside generated HTML output. An authenticated user with permissions to configure the plugin's scrollbar content can submit crafted input containing HTML or JavaScript. The plugin stores this input and later reflects it into pages served to other users. When a browser parses the response, the injected script executes in the security context of the WordPress site.

The scope-changed CVSS vector indicates that the injected script can affect resources beyond the vulnerable component, including administrator sessions and browser-accessible data across the WordPress origin.

Root Cause

The root cause is missing output encoding and input sanitization in the plugin's content-rendering paths. WordPress provides helper functions such as esc_html(), esc_attr(), and wp_kses_post() for safely emitting user data, but the plugin does not consistently apply them. Stored values flow directly from the database into the DOM without neutralization.

Attack Vector

Exploitation requires an authenticated account with sufficient rights to modify plugin settings or scrollbar content. The attacker submits a payload containing script tags, event handlers, or javascript: URIs through the plugin's input surface. Because the vulnerability is stored, the payload executes each time a targeted page loads. User interaction is required for the victim to trigger the payload, typically by visiting a page containing the malicious scrollbar content.

Refer to the Patchstack XSS Vulnerability Report for additional technical context.

Detection Methods for CVE-2025-31574

Indicators of Compromise

• Unexpected <script> tags, onerror, onload, or javascript: URIs stored in plugin options or post metadata related to custom-content-scrollbar.
• WordPress administrator sessions exhibiting unauthorized actions such as new user creation, theme edits, or plugin installations shortly after viewing affected pages.
• Outbound HTTP requests from visitor browsers to attacker-controlled domains after loading pages containing scrollbar content.

Detection Strategies

• Audit the wp_options, wp_postmeta, and plugin-specific tables for HTML or JavaScript payloads in fields associated with the Custom Content Scrollbar plugin.
• Deploy a web application firewall rule to identify script injection patterns in POST requests targeting plugin administrative endpoints.
• Enable Content Security Policy (CSP) reporting to surface inline script violations that indicate injected payloads.

Monitoring Recommendations

• Monitor WordPress audit logs for changes to plugin settings by contributor and author accounts.
• Track anomalous authenticated sessions originating from unusual geolocations or user agents interacting with the plugin.
• Alert on newly created administrator accounts or role changes following plugin content modifications.

How to Mitigate CVE-2025-31574

Immediate Actions Required

• Deactivate and remove the Custom Content Scrollbar plugin until a patched release is verified as available and installed.
• Review all existing scrollbar configurations and stored plugin content for injected scripts and remove malicious entries.
• Rotate WordPress administrator credentials and invalidate active sessions to contain potential session hijacking.

Patch Information

At the time of publication, the advisory lists all versions through 1.3 as affected without a confirmed fixed version. Monitor the Patchstack advisory and the WordPress plugin repository for an updated release, and apply it immediately upon availability.

Workarounds

• Restrict plugin configuration permissions to trusted administrator accounts only and audit existing role assignments.
• Deploy a WordPress hardening plugin or web application firewall that filters XSS payloads on plugin administrative endpoints.
• Implement a strict Content Security Policy that disallows inline scripts and untrusted script sources to limit exploit impact.

# Configuration example: enforce a restrictive Content-Security-Policy header via Apache
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'"