CVE-2025-23893: GMap Shortcode DOM-Based XSS Vulnerability

CVE-2025-23893 Overview

CVE-2025-23893 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the Manny Costales GMap Shortcode plugin for WordPress. The flaw stems from improper neutralization of input during web page generation [CWE-79]. All versions of GMap Shortcode up to and including 2.0 are affected. An authenticated attacker with low privileges can inject malicious script content that executes in a victim's browser after user interaction. The scope change indicated by the CVSS vector means the injected script can affect resources beyond the vulnerable component, including other browser contexts and user sessions.

Critical Impact

Successful exploitation allows attackers to execute arbitrary JavaScript in the browser of any user viewing a page containing the malicious shortcode, enabling session theft, credential harvesting, and administrative account takeover.

Affected Products

• Manny Costales GMap Shortcode plugin (gmap-shortcode) for WordPress
• All versions from initial release through 2.0
• WordPress sites using the plugin to embed Google Maps via shortcodes

Discovery Timeline

• 2025-01-16 - CVE-2025-23893 published to the National Vulnerability Database (NVD)
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-23893

Vulnerability Analysis

The vulnerability is classified as DOM-Based XSS, meaning the malicious payload executes when client-side JavaScript in the plugin writes attacker-controlled data into the Document Object Model (DOM) without proper sanitization or encoding. Unlike reflected or stored XSS, the injection occurs entirely within the browser's rendering pipeline.

The GMap Shortcode plugin processes shortcode attributes to render Google Maps embeds. When user-supplied attributes flow into DOM sink functions such as innerHTML, document.write, or unescaped attribute assignments, script content survives into the rendered output.

Exploitation requires user interaction, such as viewing a page containing the malicious shortcode. Because the scope changes across a trust boundary, injected scripts can access resources tied to the affected WordPress site.

Root Cause

The root cause is missing output encoding and input sanitization within the plugin's client-side rendering logic. Shortcode attributes intended for map configuration are passed to DOM APIs without applying context-appropriate escaping. WordPress helper functions such as esc_attr(), esc_html(), and wp_kses() are not enforced on the tainted data path before it reaches the browser.

Attack Vector

An attacker with contributor or author-level access to the WordPress site can craft a post or page containing a GMap shortcode with malicious attribute values. When an administrator or another user previews or views the content, the payload executes in their browser context. The attack requires low privileges to author content and user interaction to trigger the payload. See the Patchstack XSS Vulnerability Advisory for technical details.

Detection Methods for CVE-2025-23893

Indicators of Compromise

• Unexpected <script> tags, javascript: URIs, or event handler attributes (onerror, onload) embedded within GMap shortcode parameters in post content
• Outbound HTTP requests from browser sessions to unfamiliar domains following administrative page views
• New WordPress administrator accounts or modified user roles created shortly after content editors submit posts containing map shortcodes

Detection Strategies

• Audit WordPress wp_posts table entries for shortcodes containing suspicious characters such as <, >, ", or encoded equivalents in GMap attributes
• Deploy a web application firewall rule that inspects POST requests to wp-admin/post.php for shortcode payloads containing script-like content
• Review browser Content Security Policy (CSP) violation reports for inline script executions on pages rendering the GMap plugin

Monitoring Recommendations

• Enable WordPress activity logging to capture post creation and modification events by low-privileged users
• Monitor plugin file integrity and alert on any modifications to gmap-shortcode PHP or JavaScript files
• Correlate authentication events with content changes to identify session hijacking attempts following XSS exploitation

How to Mitigate CVE-2025-23893

Immediate Actions Required

• Deactivate and remove the GMap Shortcode plugin from all WordPress installations running version 2.0 or earlier until a patched release is confirmed
• Audit existing posts and pages for GMap shortcodes containing suspicious attribute values and remove malicious content
• Force password resets for administrator accounts that may have viewed pages containing untrusted shortcode content

Patch Information

At the time of publication, no vendor patch is referenced in the NVD entry for versions above 2.0. Site owners should monitor the Patchstack advisory and the WordPress plugin repository for a fixed release before re-enabling the plugin.

Workarounds

• Restrict content authoring privileges to trusted users only and disable shortcode usage for contributor-level accounts
• Implement a strict Content Security Policy (CSP) that blocks inline scripts and restricts script sources to trusted origins
• Replace the GMap Shortcode plugin with an actively maintained alternative that properly sanitizes shortcode input

# Example CSP header to reduce XSS impact in WordPress
Header set Content-Security-Policy "default-src 'self'; script-src 'self' https://maps.googleapis.com; object-src 'none'; base-uri 'self'"