CVE-2024-23902 is a cross-site request forgery (CSRF) vulnerability identified in the Jenkins GitLab Branch Source Plugin, specifically in versions 684.vea_fa_7c1e2fe3 and earlier. Jenkins is a widely used open-source automation server that facilitates continuous integration and continuous delivery (CI/CD). The GitLab Branch Source Plugin integrates Jenkins with GitLab repositories, enabling automated build and deployment workflows based on GitLab branch events. The CSRF vulnerability allows an attacker to trick an authenticated Jenkins user into executing unwanted actions by sending crafted requests that the Jenkins server processes as legitimate. In this case, the vulnerability permits attackers to connect Jenkins to an attacker-specified URL, potentially enabling malicious redirections or interactions with external systems. The CVSS v3.1 base score is 4.3 (medium severity), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), but does require user interaction (UI:R). The impact is limited to integrity (I:L) with no confidentiality or availability impact. No known exploits are currently in the wild, and no patches have been linked yet. The vulnerability is categorized under CWE-352, which corresponds to CSRF attacks. Since Jenkins is often used in enterprise environments for critical build and deployment pipelines, exploitation could lead to unauthorized manipulation of build configurations or pipeline triggers, potentially undermining software supply chain integrity.

For European organizations, this vulnerability poses a moderate risk primarily to the integrity of CI/CD pipelines managed via Jenkins with the GitLab Branch Source Plugin. Successful exploitation could allow attackers to influence build processes by redirecting Jenkins to attacker-controlled URLs, possibly injecting malicious code or triggering unauthorized builds. This could compromise the software supply chain, leading to the deployment of tampered or malicious software within corporate environments. Although confidentiality and availability impacts are not directly indicated, the integrity compromise could cascade into broader security incidents, including data breaches or operational disruptions. Organizations relying heavily on Jenkins for automated software delivery, especially those integrating GitLab repositories, are at higher risk. Given the widespread adoption of Jenkins in European IT infrastructures, particularly in technology, finance, and manufacturing sectors, the vulnerability could affect critical business operations if exploited.

1. Immediately review and restrict access to Jenkins instances, ensuring only trusted users have permissions to configure or trigger builds. 2. Implement strict Content Security Policy (CSP) headers and verify Jenkins server configurations to mitigate CSRF risks. 3. Monitor Jenkins logs for unusual requests or connections to unexpected URLs that could indicate exploitation attempts. 4. Apply any forthcoming patches or updates from the Jenkins project for the GitLab Branch Source Plugin as soon as they become available. 5. Employ network-level controls such as web application firewalls (WAFs) to detect and block CSRF attack patterns targeting Jenkins endpoints. 6. Educate Jenkins users about the risks of interacting with untrusted links or emails that could trigger CSRF attacks. 7. Consider isolating Jenkins instances or limiting plugin usage to reduce the attack surface. 8. Regularly audit plugin versions and configurations to ensure compliance with security best practices.