CVE-2024-12739 is a medium-severity vulnerability classified as CWE-79 (Cross-Site Scripting, XSS) affecting the Mobile Contact Bar WordPress plugin versions prior to 3.0.5. The vulnerability arises because the plugin fails to properly sanitize and escape certain settings inputs. This flaw allows users with high privileges, such as administrators, to inject and store malicious scripts within the plugin's settings. Notably, this exploitation is possible even when the WordPress capability 'unfiltered_html' is disabled, which is a common restriction in multisite WordPress setups to prevent script injection. The attack vector requires the attacker to have administrative privileges and some user interaction, as the CVSS vector indicates user interaction is required (UI:R). The vulnerability impacts confidentiality and integrity by enabling stored XSS attacks that could execute arbitrary JavaScript in the context of the affected site, potentially leading to session hijacking, privilege escalation, or further compromise of the WordPress environment. The CVSS score of 4.8 reflects a medium severity, considering the attack complexity is low (AC:L), but privileges are required (PR:H), and the scope is changed (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component. There are no known exploits in the wild at the time of publication, and no official patches or mitigation links have been provided yet. The vulnerability was reserved in December 2024 and published in May 2025, indicating recent discovery and disclosure. Since the affected product is a WordPress plugin, the vulnerability's impact depends on the plugin's deployment and usage within WordPress sites.

For European organizations, the impact of this vulnerability can be significant, particularly for those relying on WordPress websites that utilize the Mobile Contact Bar plugin. Stored XSS vulnerabilities can lead to the execution of malicious scripts in the browsers of site administrators or users, potentially resulting in session hijacking, theft of sensitive data, unauthorized actions on behalf of users, or further compromise of the website infrastructure. Organizations operating multisite WordPress installations are especially at risk because the vulnerability bypasses the usual 'unfiltered_html' capability restriction, which is often used to limit script injection. This could lead to widespread compromise across multiple sites managed under a single WordPress instance. The confidentiality and integrity of website data and administrative controls could be undermined, damaging organizational reputation and potentially leading to regulatory non-compliance under GDPR if personal data is exposed or manipulated. Although the vulnerability does not directly affect availability, the resulting compromise could lead to defacement or other disruptions. The medium severity suggests a moderate risk, but the requirement for high privilege limits the attack surface to insiders or compromised admin accounts. Nonetheless, targeted attacks against European organizations with valuable web assets could exploit this vulnerability to gain footholds or escalate privileges.

To mitigate this vulnerability, European organizations should first identify if they use the Mobile Contact Bar WordPress plugin and verify the version in use. Immediate steps include upgrading the plugin to version 3.0.5 or later once available, as this will likely contain the necessary sanitization and escaping fixes. Until an official patch is released, organizations should restrict administrative access to trusted personnel only and enforce strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of credential compromise. Additionally, implementing a Web Application Firewall (WAF) with custom rules to detect and block suspicious script injections in plugin settings can provide a temporary protective layer. Regularly auditing plugin settings and monitoring for unusual administrative activity or unexpected script content is recommended. For multisite WordPress setups, review and tighten capability assignments to limit the number of users with high privileges. Organizations should also consider isolating critical WordPress instances and performing regular backups to enable quick recovery in case of compromise. Finally, educating administrators about the risks of stored XSS and safe plugin management practices will help reduce the likelihood of exploitation.