CVE-2023-4423 in WP Event Manager Plugin
Summary
by MITRE • 10/25/2023
The WP Event Manager – Events Calendar, Registrations, Sell Tickets with WooCommerce plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in versions up to, and including, 3.1.37.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
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Analysis
by VulDB Data Team • 04/10/2026
The vulnerability identified as CVE-2023-4423 affects the WP Event Manager plugin for WordPress, specifically targeting versions up to and including 3.1.37.1. This represents a critical stored cross-site scripting flaw that exploits insufficient input sanitization and output escaping mechanisms within the plugin's administrative settings. The vulnerability operates through a sophisticated attack vector that leverages the plugin's administrative interface to persist malicious scripts within the WordPress installation, creating a persistent threat that can compromise user sessions and execute unauthorized code.
The technical exploitation of this vulnerability requires an authenticated attacker possessing administrator-level permissions or higher, which aligns with CWE-79 - Improper Neutralization of Input During Web Page Generation in a Web Application. The flaw manifests when malicious scripts are injected into administrative settings and subsequently stored within the database, where they await execution during page rendering. This stored XSS vulnerability particularly affects multi-site WordPress installations and environments where the unfiltered_html capability has been disabled, creating a specific attack surface that security professionals must carefully monitor and protect.
The operational impact of CVE-2023-4423 extends beyond simple script execution, as it enables attackers to potentially escalate privileges, steal user credentials, manipulate administrative settings, and compromise the entire WordPress installation. The vulnerability's persistence through stored data makes it particularly dangerous as it can affect multiple users over time without requiring repeated exploitation attempts. Attackers can craft malicious scripts that exploit the stored XSS to perform actions such as creating new administrator accounts, modifying event data, or redirecting users to malicious sites, all while maintaining stealth through the legitimate administrative interface.
Mitigation strategies for this vulnerability should prioritize immediate plugin updates to versions that address the input sanitization and output escaping deficiencies. Organizations must implement comprehensive security monitoring to detect unauthorized administrative modifications and establish strict access controls for WordPress administrative interfaces. The remediation process should include verifying that all administrative users have appropriate permissions and that the unfiltered_html capability is properly restricted. Additionally, implementing web application firewalls and security headers can provide additional defense-in-depth measures. This vulnerability demonstrates the critical importance of proper input validation and output escaping in web applications, as outlined in the OWASP Top Ten and ATT&CK framework's T1213 - Data from Information Repositories, emphasizing the need for robust security practices throughout the software development lifecycle.