CVE-2025-13979 is a vulnerability classified under CWE-267, indicating a privilege defined with unsafe actions within the Drupal Mini site module. This flaw exists in versions prior to 3.0.2, including the initial 0.0.0 release. The vulnerability allows an authenticated user with certain privileges to inject stored Cross-Site Scripting (XSS) payloads into the application. Stored XSS occurs when malicious scripts are permanently stored on the target server, such as in a database, and executed when other users access the affected content. The CVSS 3.1 base score of 5.4 reflects a medium severity, with attack vector being network-based (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), and impacting confidentiality and integrity (C:L/I:L) but not availability (A:N). The unsafe privilege configuration means that the permissions granted to certain roles allow actions that can be exploited to inject malicious scripts, potentially leading to session hijacking, data theft, or further compromise of user accounts. Although no known exploits are currently reported in the wild, the vulnerability poses a tangible risk to Drupal sites that have not upgraded. The lack of a patch link suggests that remediation involves upgrading to version 3.0.2 or later once available. This vulnerability is particularly concerning for web applications that rely on Drupal Mini site for content management and user interaction, as stored XSS can affect multiple users and lead to widespread compromise.

For European organizations, this vulnerability can lead to unauthorized disclosure of sensitive information and compromise of user accounts through stored XSS attacks. Attackers exploiting this flaw could execute malicious scripts in the context of other users, potentially stealing session tokens, redirecting users to malicious sites, or performing actions on behalf of legitimate users. This undermines the confidentiality and integrity of data managed by Drupal Mini site installations. Organizations in sectors such as government, finance, healthcare, and critical infrastructure that use Drupal-based web portals are at higher risk due to the sensitive nature of their data and the potential reputational damage from a successful attack. The medium severity rating indicates that while the vulnerability is not critical, it still requires timely remediation to prevent exploitation. Since exploitation requires authenticated privileges, insider threats or compromised accounts could be leveraged to exploit this vulnerability. The absence of user interaction lowers the barrier for exploitation once privileges are obtained. Overall, the impact includes potential data breaches, loss of user trust, and increased risk of further attacks leveraging the initial XSS foothold.

European organizations should immediately inventory their Drupal Mini site installations to identify affected versions prior to 3.0.2. Until an official patch or upgrade is applied, restrict privileges associated with the vulnerable actions to the minimum necessary users and roles, applying the principle of least privilege. Implement Web Application Firewalls (WAF) with rules to detect and block common XSS payloads targeting Drupal endpoints. Conduct thorough code reviews and input validation enhancements to sanitize user inputs and outputs within the Mini site module. Monitor logs for unusual activity indicative of stored XSS exploitation attempts, such as unexpected script injections or anomalous user behavior. Educate administrators and developers about the risks of unsafe privilege assignments and encourage prompt application of security updates once available. Additionally, consider deploying Content Security Policy (CSP) headers to mitigate the impact of injected scripts. Regularly back up Drupal site data and configurations to enable rapid recovery if an attack occurs. Finally, coordinate with Drupal community channels to stay informed about patches and advisories related to this vulnerability.