CVE-2024-9416 is a stored Cross-Site Scripting (XSS) vulnerability identified in the Modula Image Gallery plugin for WordPress, specifically versions up to 5.0.36. The vulnerability stems from improper neutralization of input during web page generation, categorized under CWE-79. The root cause is insufficient sanitization and escaping of user-supplied attributes in the plugin's bundled FancyBox JavaScript library. Authenticated attackers with contributor-level privileges or higher can exploit this flaw by injecting arbitrary JavaScript code into pages managed by the plugin. Once injected, the malicious scripts execute automatically whenever any user accesses the affected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of users. The vulnerability requires no user interaction beyond visiting the infected page, but does require the attacker to have authenticated access with at least contributor rights, which are commonly granted to trusted users or content creators. The CVSS v3.1 score is 6.4, reflecting medium severity with network attack vector, low attack complexity, and partial impact on confidentiality and integrity but no impact on availability. No public exploits have been reported yet, but the vulnerability poses a significant risk to WordPress sites using this plugin, which is popular for image gallery management. The vulnerability highlights the importance of proper input validation and output encoding in web applications, especially in plugins that handle user-generated content.

The impact of CVE-2024-9416 is primarily on the confidentiality and integrity of affected WordPress sites. Successful exploitation can lead to session hijacking, theft of sensitive information such as cookies or authentication tokens, and unauthorized actions performed with the victim's privileges. This can result in defacement, data leakage, or further compromise of the website and its users. Since the vulnerability is stored XSS, the malicious payload persists on the site and affects all visitors to the compromised page, increasing the attack surface. Organizations relying on the Modula Image Gallery plugin risk reputational damage, loss of user trust, and potential regulatory consequences if user data is exposed. The requirement for contributor-level access reduces the risk from anonymous attackers but does not eliminate it, as many sites grant such privileges to multiple users. The vulnerability could be leveraged as a foothold for more advanced attacks, including privilege escalation or distribution of malware. Given WordPress's widespread use globally, the potential impact spans a broad range of industries and sectors.

To mitigate CVE-2024-9416, organizations should immediately update the Modula Image Gallery plugin to a patched version once released by the vendor. Until a patch is available, restrict contributor-level access to trusted users only and audit existing users for unnecessary privileges. Implement Web Application Firewall (WAF) rules to detect and block suspicious input patterns targeting the FancyBox library or typical XSS payloads. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected pages. Regularly scan the website for injected scripts or anomalies in gallery pages. Educate content contributors about safe input practices and monitor plugin updates from wpchill. Additionally, consider isolating or disabling the FancyBox JavaScript library if feasible or replacing it with a secure alternative. Conduct thorough security testing on all user-generated content features to prevent similar vulnerabilities. Maintain regular backups to enable quick restoration if compromise occurs.