CVE-2025-13907 identifies a stored cross-site scripting (XSS) vulnerability in the tunilame CSS3 Buttons plugin for WordPress, present in all versions up to and including 0.1. The vulnerability arises from insufficient input sanitization and output escaping on user-supplied attributes within the plugin's 'button' shortcode. Authenticated attackers with contributor-level or higher privileges can inject arbitrary JavaScript code that is stored persistently in the WordPress database and executed in the browsers of users who visit the affected pages. This stored XSS flaw allows attackers to perform actions such as session hijacking, privilege escalation, or defacement by executing malicious scripts in the context of the victim's browser. The vulnerability does not require user interaction beyond visiting the compromised page, but it does require the attacker to have contributor-level access, which limits the attack surface to insiders or compromised accounts. The CVSS v3.1 base score is 6.4 (medium severity), reflecting network attack vector, low attack complexity, privileges required, no user interaction, and partial impact on confidentiality and integrity but no impact on availability. No patches or fixes have been released at the time of publication, and no known exploits are currently in the wild. The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation).

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of their WordPress-based web properties. Attackers with contributor-level access—such as disgruntled employees, compromised accounts, or third-party collaborators—can inject malicious scripts that execute in the browsers of site visitors, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions performed on behalf of users. This can damage organizational reputation, lead to data breaches, and undermine trust in public-facing websites. Since WordPress is widely used across Europe for corporate, governmental, and media websites, the impact can be broad, especially for organizations that rely on community-contributed content or have multiple contributors. The vulnerability does not affect availability directly but can be leveraged as part of a larger attack chain. The absence of patches increases the urgency for temporary mitigations. The requirement for authenticated access reduces the risk from external anonymous attackers but highlights the importance of internal access controls and monitoring.

European organizations should immediately audit their WordPress installations to identify the presence of the tunilame CSS3 Buttons plugin and its version. Since no official patches are available, organizations should consider disabling or uninstalling the plugin until a fix is released. Restrict contributor-level access strictly to trusted users and enforce strong authentication mechanisms, including multi-factor authentication, to reduce the risk of account compromise. Implement web application firewalls (WAFs) with custom rules to detect and block suspicious shortcode inputs or script injections related to this plugin. Conduct regular security training for contributors to recognize phishing and social engineering attempts that could lead to account takeover. Monitor logs for unusual contributor activity and review content submissions for malicious code. Additionally, apply Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. Once a patch is available, prioritize immediate deployment. Consider using security plugins that sanitize shortcode inputs or provide additional input validation.