CVE-2025-11926: Related Posts Lite Plugin XSS Vulnerability

CVE-2025-11926 Overview

CVE-2025-11926 is a Stored Cross-Site Scripting (XSS) vulnerability in the Related Posts Lite plugin for WordPress. The flaw affects all versions up to and including 1.12. The plugin fails to properly sanitize input and escape output in its admin settings interface. Authenticated attackers holding administrator-level permissions can inject arbitrary web scripts. Injected payloads execute when other users visit affected pages. The issue only applies to multi-site installations and installations where unfiltered_html has been disabled. The vulnerability is tracked under CWE-79: Improper Neutralization of Input During Web Page Generation.

Critical Impact
Authenticated administrators on multi-site WordPress installations can inject persistent JavaScript that executes in the browser context of any visitor to affected pages.

Affected Products

Related Posts Lite plugin for WordPress, versions up to and including 1.12
WordPress multi-site installations running the affected plugin
WordPress installations where the unfiltered_html capability has been disabled

Discovery Timeline

2025-10-18 - CVE-2025-11926 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-11926

Vulnerability Analysis

The Related Posts Lite plugin processes administrator-supplied values in its settings interface without applying adequate sanitization on input or escaping on output. When these stored values are later rendered inside plugin-generated markup, injected JavaScript executes in the browser of any user viewing the page. Because the payload persists in the WordPress database, every subsequent page load re-triggers the script. The scope change (S:C) reflects the ability of injected script to affect resources beyond the vulnerable plugin, such as authenticated session cookies or DOM contents belonging to the broader WordPress site.

This vulnerability primarily matters in multi-tenant WordPress environments. In standard single-site installations, administrators already possess the unfiltered_html capability, which allows arbitrary HTML and script content by design. The security boundary only exists where WordPress explicitly strips that capability, such as multi-site networks or hardened deployments.

Root Cause

The plugin does not call WordPress sanitization helpers such as sanitize_text_field() on stored admin settings, nor does it apply escaping functions such as esc_html() or esc_attr() when rendering those values. This omission allows raw <script> tags or event-handler attributes to survive the storage and retrieval cycle intact.

Attack Vector

An authenticated attacker with administrator privileges on a subsite of a WordPress multi-site network submits a crafted payload through the Related Posts Lite settings form. The payload is written to the WordPress options table. Any user, including super administrators visiting the subsite, executes the injected script upon loading a page that renders the affected settings. This enables session theft, forced administrative actions, or pivot into higher-privilege accounts.

A public proof-of-concept has been published. See the GitHub XSS PoC Repository and the Wordfence Vulnerability Report for technical details.

Detection Methods for CVE-2025-11926

Indicators of Compromise

Unexpected <script> tags, onerror, onload, or javascript: URIs stored in the wp_options table entries associated with the Related Posts Lite plugin.
Outbound HTTP requests from browser sessions to unfamiliar domains immediately after loading pages that include related-posts widgets.
New or modified WordPress administrator accounts appearing shortly after a settings update by an existing administrator.

Detection Strategies

Audit plugin option values for HTML control characters and script constructs using database queries or WordPress CLI: wp option get against Related Posts Lite keys.
Compare installed plugin version against 1.12; any version at or below this threshold is vulnerable.
Review WordPress activity logs for update_option events tied to Related Posts Lite that were followed by anomalous frontend behavior.

Monitoring Recommendations

Enable an audit-logging plugin to capture administrator setting changes across all subsites in a multi-site network.
Alert on Content Security Policy (CSP) violation reports pointing to inline script execution on pages served by the plugin.
Monitor administrator session activity for privilege escalation attempts targeting super administrator accounts on multi-site networks.

How to Mitigate CVE-2025-11926

Immediate Actions Required

Upgrade the Related Posts Lite plugin to a version newer than 1.12 once the vendor publishes a fix. Track updates on the WordPress Plugin Page.
Audit administrator accounts on multi-site installations and remove any accounts that are not strictly required.
Review the plugin settings for any injected content and remove suspicious payloads from the database.

Patch Information

At the time of publication, no fixed version has been confirmed in the NVD entry. Consult the WordPress Plugin Version History and the Wordfence Vulnerability Report for updated remediation guidance.

Workarounds

Deactivate and remove the Related Posts Lite plugin until a patched release is available.
Restrict administrator permissions on WordPress multi-site subsites so that fewer accounts can modify plugin settings.
Deploy a strict Content Security Policy that disallows inline scripts on frontend pages, limiting the impact of stored XSS payloads.
Consider re-enabling unfiltered_html risk mitigations via a web application firewall (WAF) rule that inspects POST requests to wp-admin/options.php for script-tag content.

bash

# Verify plugin version via WP-CLI
wp plugin get related-posts-lite --field=version

# Deactivate the plugin network-wide on a multi-site install
wp plugin deactivate related-posts-lite --network

# Inspect stored plugin options for injected script content
wp option list --search='*related_posts*' --format=table