CVE-2024-11875 in Add Infos to the Events Calendar Plugin
Summary
by MITRE • 12/12/2024
The Add infos to the events calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'fuss' shortcode in all versions up to, and including, 1.4.1 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 02/18/2025
The vulnerability identified as CVE-2024-11875 affects the Add infos to the events calendar plugin for WordPress, specifically targeting versions up to and including 1.4.1. This represents a critical security flaw that undermines the integrity of WordPress installations by enabling malicious actors to execute persistent cross-site scripting attacks. The vulnerability resides within the plugin's 'fuss' shortcode implementation, which fails to properly sanitize or escape user-supplied input parameters, creating an exploitable vector for attackers to inject malicious scripts into the web application's output.
The technical flaw manifests through insufficient input validation mechanisms that should have been implemented to filter and sanitize all user-provided data before processing. When the plugin processes the 'fuss' shortcode, it accepts attributes from users without adequate sanitization procedures, allowing attackers to inject malicious JavaScript code through carefully crafted input parameters. This weakness directly maps to CWE-79, which describes Cross-Site Scripting vulnerabilities resulting from inadequate input validation and output escaping. The vulnerability specifically affects authenticated users who possess contributor-level access or higher privileges, making it particularly dangerous as it leverages legitimate user permissions to execute malicious payloads.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to establish persistent footholds within WordPress environments. Once successfully exploited, authenticated attackers can inject scripts that will execute whenever any user accesses pages containing the malicious shortcode, potentially leading to session hijacking, data exfiltration, or further compromise of the WordPress installation. The vulnerability's exploitation requires only contributor-level access, which is often more readily available than administrator privileges, making it an attractive target for attackers seeking to establish long-term access to WordPress sites. This weakness can be exploited to redirect users to malicious domains, steal cookies and session information, or even modify content on the affected sites.
Mitigation strategies for CVE-2024-11875 should prioritize immediate plugin updates to versions that address the sanitization issues, as this represents the most direct solution to the vulnerability. Administrators should also implement strict access controls and privilege management to limit contributor-level access to only trusted users, while monitoring for suspicious shortcode usage within the WordPress environment. Additional defensive measures include implementing content security policies that restrict script execution, conducting regular security audits of plugin installations, and establishing monitoring protocols to detect unauthorized shortcode modifications. The vulnerability demonstrates the importance of proper input sanitization and output escaping as fundamental security practices, aligning with ATT&CK technique T1566.001 which covers the exploitation of vulnerabilities in web applications through injection attacks. Organizations should also consider implementing web application firewalls and regular security assessments to identify similar vulnerabilities in other plugins and themes that may be susceptible to similar cross-site scripting attacks.