CVE-2024-3031 identifies a stored cross-site scripting (XSS) vulnerability in the Fluid Notification Bar plugin for WordPress, developed by shrinitech. This vulnerability affects all versions up to and including 3.2.3. The root cause is improper neutralization of input during web page generation, specifically insufficient sanitization and escaping of administrator-supplied input in the plugin's settings interface. An attacker with administrator-level permissions can inject arbitrary JavaScript code into the notification bar content, which is then stored and rendered on pages accessed by other users. This vulnerability is limited to multi-site WordPress installations or installations where the unfiltered_html capability is disabled, as these configurations restrict HTML filtering and allow the malicious script to persist. The attack vector requires network access (remote) and high privileges (administrator), with no user interaction needed for the payload to execute. The vulnerability impacts confidentiality and integrity by enabling script execution in the context of affected users, potentially leading to session hijacking, credential theft, or unauthorized actions. The CVSS v3.1 base score is 4.4, reflecting medium severity due to the high privilege requirement and limited attack surface. No public exploits have been reported to date, but the vulnerability poses a risk in environments where multiple users access the injected content. The absence of official patches at the time of reporting necessitates immediate attention from administrators to mitigate risk.

The primary impact of CVE-2024-3031 is the potential compromise of user confidentiality and integrity within affected WordPress multi-site environments using the Fluid Notification Bar plugin. An attacker with administrator privileges can inject malicious scripts that execute in the browsers of other users who view the notification bar, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions performed on behalf of users. Although the vulnerability does not affect availability, the breach of trust and data confidentiality can have significant reputational and operational consequences. Organizations relying on multi-site WordPress installations with this plugin are at risk, especially those with multiple administrators or users accessing the notification bar content. The requirement for administrator-level access limits the likelihood of external exploitation but raises concerns about insider threats or compromised admin accounts. The medium CVSS score reflects these factors, indicating a moderate but non-trivial risk. Failure to address this vulnerability could lead to targeted attacks against high-value WordPress sites, particularly in sectors where WordPress multi-site is common, such as education, media, and large enterprises.

To mitigate CVE-2024-3031, organizations should first verify if they are running multi-site WordPress installations with the Fluid Notification Bar plugin version 3.2.3 or earlier. Immediate steps include restricting administrator access to trusted personnel only and auditing admin accounts for suspicious activity. Since no official patch is currently available, administrators should consider temporarily disabling the plugin or limiting its use in multi-site environments. Implementing a Web Application Firewall (WAF) with custom rules to detect and block suspicious script injection attempts in admin settings can reduce risk. Additionally, enabling strict Content Security Policy (CSP) headers can help mitigate the impact of injected scripts by restricting script execution sources. Regularly monitoring logs for unusual admin activity and scanning for injected scripts in notification bar content is recommended. Once an official patch is released, prompt updating of the plugin is essential. Finally, educating administrators on secure input handling and the risks of XSS vulnerabilities can prevent inadvertent exploitation.