CVE-2025-47621: Meks Flexible Shortcodes Stored XSS Flaw

CVE-2025-47621 Overview

CVE-2025-47621 is a stored Cross-Site Scripting (XSS) vulnerability [CWE-79] in the Meks Flexible Shortcodes plugin for WordPress. The flaw affects all versions of meks-flexible-shortcodes up to and including 1.3.6. Authenticated attackers with low privileges can inject persistent JavaScript payloads that execute in the browsers of users who view affected pages. The issue stems from improper neutralization of user-supplied input during web page generation.

Critical Impact
Stored XSS enables attackers to hijack sessions, steal credentials, deface content, and pivot to administrative account takeover when a WordPress administrator views a poisoned page.

Affected Products

Meks Flexible Shortcodes WordPress plugin (meks-flexible-shortcodes)
All versions from unspecified initial release through 1.3.6
WordPress sites with the vulnerable plugin activated

Discovery Timeline

2025-05-07 - CVE CVE-2025-47621 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-47621

Vulnerability Analysis

The vulnerability is a stored Cross-Site Scripting flaw classified under [CWE-79]. Meks Flexible Shortcodes fails to sanitize or encode user-controlled input before rendering it inside shortcode output on WordPress pages. An authenticated contributor-level user can embed malicious HTML or JavaScript through the plugin's shortcode parameters. The payload is stored in the WordPress database and executed each time a visitor renders the affected content. Because the attack crosses a security scope (contributor injecting script that runs in an administrator's browser), the flaw carries user interaction and scope-change characteristics.

Root Cause

The plugin does not apply WordPress escaping functions such as esc_html(), esc_attr(), or wp_kses() to attributes or content passed through its shortcodes. Input flows directly from the shortcode processor into the rendered HTML response without validation or output encoding.

Attack Vector

Exploitation requires network access to the WordPress site and an authenticated account with post-editing privileges. The attacker also relies on a victim, typically an editor or administrator, viewing the page containing the malicious shortcode. Successful exploitation executes attacker-controlled JavaScript in the victim's authenticated session, enabling cookie theft, forced administrative actions, or persistent backdoor injection through plugin installation.

Refer to the Patchstack XSS Vulnerability Advisory for advisory-level technical detail.

Detection Methods for CVE-2025-47621

Indicators of Compromise

Post or page content containing shortcode attributes with <script>, onerror=, onload=, or javascript: payloads
Unexpected outbound requests from browsers of administrators to attacker-controlled domains after loading pages that use plugin shortcodes
New administrator accounts, unfamiliar plugins, or modified wp-config.php following administrator page views
Database entries in wp_posts containing encoded script fragments within Meks shortcode syntax

Detection Strategies

Query the WordPress database for shortcode entries containing HTML event handlers or <script> tags
Deploy web application firewall rules that inspect POST requests to wp-admin/post.php for XSS patterns inside plugin shortcode parameters
Monitor plugin version inventory and flag WordPress installations running meks-flexible-shortcodes version 1.3.6 or earlier

Monitoring Recommendations

Enable WordPress audit logging for post edits performed by contributor and author roles
Alert on Content Security Policy (CSP) violations reported by administrator browsers
Track creation of new privileged accounts and plugin installations following suspicious content edits

How to Mitigate CVE-2025-47621

Immediate Actions Required

Update Meks Flexible Shortcodes to a version newer than 1.3.6 once a patched release is available
Audit existing posts and pages for malicious content injected through plugin shortcodes
Restrict contributor and author role assignments to trusted users only
Rotate administrator session cookies and passwords if suspicious shortcode content is discovered

Patch Information

At the time of publication, the advisory lists all versions through 1.3.6 as affected. Monitor the Patchstack advisory and the WordPress plugin repository for a fixed release, then apply it across all affected sites.

Workarounds

Deactivate and remove the Meks Flexible Shortcodes plugin until a patched version is released
Deploy a virtual patch via a WordPress-aware web application firewall to strip script content from shortcode parameters
Enforce a strict Content Security Policy that blocks inline script execution on the WordPress front end
Limit post-editing capabilities to trusted administrators as a temporary compensating control

bash

# Disable the vulnerable plugin using WP-CLI
wp plugin deactivate meks-flexible-shortcodes
wp plugin delete meks-flexible-shortcodes