CVE-2024-10054 is a medium-severity vulnerability affecting the Happyforms WordPress plugin versions prior to 1.26.3. The vulnerability is a Stored Cross-Site Scripting (XSS) flaw classified under CWE-79. It arises because certain settings within the plugin are not properly sanitized or escaped. This improper handling allows users with high privileges, such as administrators, to inject malicious scripts that are stored persistently within the plugin's data. Notably, this vulnerability can be exploited even when the WordPress capability 'unfiltered_html' is disabled, such as in multisite environments, which typically restricts HTML content editing to trusted users. The attack requires the attacker to have high privileges (admin level) and some user interaction (e.g., accessing the affected settings or pages where the malicious script executes). The vulnerability has a CVSS 3.1 base score of 4.8, indicating a medium severity level. The vector string (AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N) shows that the attack can be performed remotely over the network with low attack complexity but requires high privileges and user interaction, and it impacts confidentiality and integrity with a scope change. There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. The vulnerability was published on May 15, 2025, and was assigned by WPScan. The root cause is insufficient input sanitization and escaping in plugin settings, which enables stored XSS attacks that can compromise site security by executing arbitrary JavaScript in the context of authenticated users or administrators.

For European organizations using WordPress sites with the vulnerable Happyforms plugin, this vulnerability poses a risk primarily to site integrity and confidentiality. An attacker with admin privileges could inject malicious scripts that execute in the browsers of other administrators or privileged users, potentially leading to session hijacking, credential theft, or unauthorized actions within the WordPress admin interface. This could result in unauthorized content modification, data leakage, or further compromise of the website and underlying infrastructure. Although the vulnerability requires high privileges to exploit, the impact is significant in environments where multiple administrators manage content or settings, such as corporate websites, e-commerce platforms, or government portals. The scope change indicated in the CVSS vector suggests that the vulnerability could affect resources beyond the initially compromised component, potentially impacting other parts of the WordPress installation or connected systems. Given the widespread use of WordPress across Europe, especially in small and medium enterprises and public sector websites, exploitation could lead to reputational damage, regulatory compliance issues (e.g., GDPR violations if personal data is exposed), and operational disruptions.

1. Immediate upgrade: Organizations should upgrade the Happyforms plugin to version 1.26.3 or later as soon as it becomes available to ensure the vulnerability is patched. 2. Privilege review: Restrict administrative privileges to only trusted users and regularly audit user roles to minimize the risk of malicious insiders exploiting this vulnerability. 3. Input validation: Implement additional server-side input validation and sanitization for plugin settings if custom modifications are possible, to prevent injection of malicious scripts. 4. Content Security Policy (CSP): Deploy a strict CSP header to reduce the impact of XSS by restricting the execution of unauthorized scripts. 5. Monitoring and logging: Enable detailed logging of administrative actions and monitor for unusual activity that could indicate exploitation attempts. 6. User awareness: Train administrators on the risks of XSS and encourage caution when entering or approving content in plugin settings. 7. Backup and recovery: Maintain regular backups of WordPress sites to enable quick restoration in case of compromise. 8. Disable or limit untrusted plugins: Evaluate the necessity of the Happyforms plugin and consider alternatives if the risk profile is unacceptable.