CVE-2026-1941: WP Event Aggregator XSS Vulnerability

CVE-2026-1941 Overview

The WP Event Aggregator plugin for WordPress contains a Stored Cross-Site Scripting (XSS) vulnerability in the wp_events shortcode functionality. This vulnerability affects all versions up to and including 1.8.7 and stems from insufficient input sanitization and output escaping on user-supplied attributes. Authenticated attackers with Contributor-level access or above can exploit this flaw to inject arbitrary web scripts into pages, which execute whenever a user accesses an affected page.

Critical Impact

Attackers with low-privilege WordPress accounts can inject persistent malicious scripts that execute in the browsers of any user viewing the compromised page, potentially leading to session hijacking, credential theft, or further site compromise.

Affected Products

• WP Event Aggregator plugin for WordPress versions up to and including 1.8.7
• WordPress sites using the wp_events shortcode functionality
• Any WordPress installation with Contributor or higher user roles enabled

Discovery Timeline

• February 18, 2026 - CVE-2026-1941 published to NVD
• February 18, 2026 - Last updated in NVD database

Technical Details for CVE-2026-1941

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists within the WP Event Aggregator plugin's shortcode processing functionality. The plugin fails to properly sanitize and escape user-supplied attributes when processing the wp_events shortcode. This allows authenticated users with Contributor-level permissions to embed malicious JavaScript payloads that persist in the WordPress database and execute in the context of any user's browser session when they view the affected page.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The attack can be executed remotely over the network without requiring user interaction beyond accessing the compromised page. Due to the changed scope characteristic, the vulnerability's impact extends beyond the vulnerable component itself, potentially affecting other components within the same origin.

Root Cause

The root cause of this vulnerability lies in the class-wp-event-aggregator-cpt.php file, specifically in how user-supplied shortcode attributes are processed. The plugin accepts attribute values from the shortcode without applying proper sanitization functions such as esc_attr(), esc_html(), or wp_kses(). When these unsanitized values are rendered in the HTML output, any embedded JavaScript code executes in the user's browser.

The vulnerable code sections have been identified at multiple locations within the CPT (Custom Post Type) class file, including lines 56, 567, and 761, where attribute values are processed and output without adequate escaping.

Attack Vector

The attack exploits the network-accessible WordPress post editor interface. An attacker who has gained Contributor-level access (or higher) to a WordPress installation can create or edit a post containing the wp_events shortcode with malicious attribute values.

Once the post containing the malicious shortcode is published or saved for preview, the injected script persists in the database. When any user—including administrators—views the page, the malicious script executes within their browser session. This can lead to session cookie theft, keylogging, phishing overlay injection, or redirects to malicious sites.

The attack does not require any additional user interaction beyond normal page viewing, making it particularly dangerous in multi-user WordPress environments.

Detection Methods for CVE-2026-1941

Indicators of Compromise

• Unexpected JavaScript code appearing in post content containing wp_events shortcodes
• Unusual shortcode attribute values containing script tags, event handlers (onerror, onload, onclick), or encoded JavaScript
• Browser security warnings or Content Security Policy violations when viewing event-related pages
• User reports of strange behavior, redirects, or popups when viewing events

Detection Strategies

• Review WordPress posts and pages for wp_events shortcodes with suspicious attribute values containing HTML entities or script syntax
• Implement Content Security Policy (CSP) headers to detect and block inline script execution
• Monitor WordPress database tables for XSS patterns in post content and metadata
• Enable WordPress audit logging to track shortcode usage and post modifications by Contributor-level users

Monitoring Recommendations

• Deploy Web Application Firewall (WAF) rules to detect XSS payload patterns in shortcode attributes
• Implement real-time monitoring for changes to posts containing event-related shortcodes
• Configure browser-based XSS detection tools to alert on potential script injection
• Review user activity logs for Contributor accounts creating or modifying event-related content

How to Mitigate CVE-2026-1941

Immediate Actions Required

• Update the WP Event Aggregator plugin to the latest patched version immediately
• Audit existing posts and pages for potentially malicious wp_events shortcode usage
• Review and revoke unnecessary Contributor-level access for untrusted users
• Implement Content Security Policy headers as an additional defense layer

Patch Information

A security patch has been released to address this vulnerability. The fix is available in WordPress Changeset #3455440, which implements proper output escaping for shortcode attributes. Site administrators should update to the patched version through the WordPress plugin update mechanism. For detailed vulnerability information, refer to the Wordfence Vulnerability Report.

Workarounds

• Temporarily disable the WP Event Aggregator plugin until the update can be applied
• Restrict Contributor and Author role capabilities to prevent shortcode usage in posts
• Deploy WAF rules to filter potentially malicious shortcode attributes
• Remove or restrict access to the wp_events shortcode functionality using WordPress hooks

# WordPress CLI command to update the plugin
wp plugin update wp-event-aggregator

# Verify the installed version after update
wp plugin get wp-event-aggregator --field=version

# Search for potentially malicious shortcode usage in posts
wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%[wp_events%script%' OR post_content LIKE '%[wp_events%onerror%'"