CVE-2025-53678 is a vulnerability identified in the Jenkins User1st uTester Plugin version 1.1 and earlier. The core issue lies in the insecure storage of the uTester JWT (JSON Web Token) token within the plugin's global configuration file on the Jenkins controller. Specifically, the token is stored unencrypted on the file system, making it accessible to any user who has file system access to the Jenkins controller. JWT tokens are typically used for authentication and authorization purposes, and their compromise can lead to unauthorized access or privilege escalation within the Jenkins environment. Since Jenkins is a widely used automation server for continuous integration and continuous delivery (CI/CD), exposure of such tokens can allow attackers to impersonate legitimate users or services, potentially leading to unauthorized pipeline execution, code injection, or data exfiltration. The vulnerability does not require user interaction but does require file system access to the Jenkins controller, which may be limited to certain users or roles. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. No patches or mitigation links have been provided by the vendor as of the publication date, indicating that users must proactively secure their Jenkins environments and monitor for updates.

For European organizations, this vulnerability poses a significant risk, especially for those relying heavily on Jenkins for their software development lifecycle. Unauthorized access to JWT tokens could allow attackers to manipulate build pipelines, inject malicious code, or disrupt deployment processes, potentially leading to compromised software integrity and availability. This can have downstream effects on product security, customer trust, and regulatory compliance, particularly under GDPR where data integrity and security are paramount. Organizations in sectors such as finance, healthcare, and critical infrastructure, which often use Jenkins for automated deployments, may face increased risk of operational disruption or data breaches. Additionally, the exposure of authentication tokens could facilitate lateral movement within internal networks, escalating the severity of an attack. Given the lack of encryption for sensitive tokens, insider threats or attackers who gain limited access to the Jenkins controller file system can exploit this vulnerability without needing to bypass network defenses.

To mitigate this vulnerability, European organizations should immediately audit access controls to the Jenkins controller file system, ensuring that only trusted administrators have read/write permissions. Implement strict role-based access controls (RBAC) and consider isolating the Jenkins controller on a secure network segment with limited access. Until an official patch is released, organizations can manually encrypt the configuration files or store JWT tokens in secure vaults or credential management systems external to Jenkins. Regularly rotate JWT tokens to limit the window of exposure if a token is compromised. Monitoring and alerting should be enhanced to detect unusual access patterns or unauthorized file system access on Jenkins controllers. Additionally, organizations should keep abreast of Jenkins plugin updates and apply patches promptly once available. Employing containerization or ephemeral Jenkins controllers can also reduce persistent exposure of sensitive files. Finally, educating Jenkins administrators about the risks of storing sensitive tokens unencrypted and enforcing secure plugin configurations will help reduce the attack surface.