CVE-2026-5451: Leaflet Map WordPress Plugin XSS Flaw

CVE-2026-5451 Overview

The Extensions for Leaflet Map plugin for WordPress is vulnerable to Stored Cross-Site Scripting (XSS) via the elevation-track shortcode in all versions up to, and including, 4.14. This vulnerability stems from insufficient input sanitization and output escaping on user-supplied attributes within the shortcode functionality. Authenticated attackers with Contributor-level access or above can exploit this flaw to inject arbitrary web scripts into pages, which will execute whenever a user accesses an affected page.

Critical Impact

Authenticated attackers can persistently inject malicious JavaScript code that executes in the context of other users' browsers, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of legitimate users.

Affected Products

• Extensions for Leaflet Map plugin for WordPress versions up to and including 4.14
• WordPress installations utilizing the vulnerable plugin versions
• Sites allowing Contributor-level or higher user access with the plugin enabled

Discovery Timeline

• 2026-04-08 - CVE CVE-2026-5451 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2026-5451

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists within the elevation-track shortcode handler in the Extensions for Leaflet Map plugin. The vulnerable code paths are located in functions.php and multielevation.php within the plugin's PHP directory. When processing user-supplied shortcode attributes, the plugin fails to properly sanitize input data and escape output, creating an injection point for malicious scripts.

The attack requires authentication with at least Contributor-level privileges, which is a common role in multi-author WordPress environments. Once an attacker crafts a malicious shortcode with embedded JavaScript payload, the script persists in the database and executes in the browsers of all users who view the affected page—including administrators.

The scope change characteristic of this vulnerability means that the malicious scripts execute within a different security context than the vulnerable component, potentially affecting the broader WordPress application and its users.

Root Cause

The root cause of this vulnerability is improper input validation (CWE-79) in the shortcode processing functions. Specifically, the plugin does not adequately sanitize user-controlled attributes passed to the elevation-track shortcode before incorporating them into the rendered HTML output. The vulnerable code in functions.php at line 168 and multielevation.php at line 227 fails to apply proper escaping functions such as esc_attr(), esc_html(), or wp_kses() that would neutralize potentially malicious input.

Attack Vector

The attack vector is network-based, requiring an authenticated attacker to access the WordPress dashboard with content creation capabilities. The exploitation flow involves:

1. An attacker with Contributor-level access creates or edits a post/page
2. The attacker embeds a malicious elevation-track shortcode containing JavaScript payload within the shortcode attributes
3. When the page is published or previewed, the unsanitized payload is stored in the database
4. Any user (including administrators) visiting the page triggers execution of the injected script in their browser context
5. The malicious script can steal session cookies, redirect users, deface content, or perform actions as the victim user

The vulnerability can be exploited through the shortcode editor in WordPress without requiring any specialized tools, as the malicious payload is delivered through the normal WordPress content management interface.

Detection Methods for CVE-2026-5451

Indicators of Compromise

• Unusual JavaScript code patterns in posts or pages utilizing the elevation-track shortcode
• Unexpected shortcode attributes containing script tags, event handlers (e.g., onload, onerror, onclick), or JavaScript URIs
• Database entries in wp_posts table containing encoded or obfuscated script content within shortcode parameters
• Browser console errors or unexpected network requests when viewing pages with the Leaflet Map extension

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect XSS patterns in POST requests targeting WordPress content endpoints
• Review WordPress audit logs for content modifications by Contributor-level users that include suspicious shortcode syntax
• Deploy content security policies (CSP) to detect and block inline script execution from unauthorized sources
• Regularly scan database content for common XSS payload signatures within shortcode-related fields

Monitoring Recommendations

• Enable comprehensive WordPress activity logging to track all content changes and user actions
• Monitor for unusual patterns of page edits, particularly those involving Leaflet Map shortcodes
• Implement real-time alerting for Content Security Policy violations that may indicate XSS attempts
• Review server access logs for suspicious patterns of requests to pages containing the vulnerable shortcode

How to Mitigate CVE-2026-5451

Immediate Actions Required

• Update the Extensions for Leaflet Map plugin to version 4.15 or later immediately
• Audit existing content for any potentially malicious elevation-track shortcode usage
• Review user accounts with Contributor-level access or higher and verify their legitimacy
• Consider temporarily disabling the plugin until the patch can be applied if immediate update is not possible

Patch Information

The vulnerability has been addressed in version 4.15 of the Extensions for Leaflet Map plugin. The patched files include functions.php and multielevation.php with proper input sanitization and output escaping implemented. The patches can be reviewed in the WordPress Plugin Trac for functions.php and multielevation.php. Additional vulnerability details are available from the Wordfence threat intelligence advisory.

Workarounds

• Restrict Contributor-level and Author-level user roles from using shortcodes by implementing a custom capability filter
• Implement a Content Security Policy (CSP) header to mitigate the impact of potential XSS exploitation
• Use a WordPress security plugin with real-time XSS filtering capabilities to scan and sanitize shortcode content
• Consider temporarily removing the elevation-track shortcode functionality by deregistering it until the plugin is updated

# Example: Add CSP header to Apache configuration
# Add to .htaccess or Apache virtual host configuration
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline';"