CVE-2025-59474 is a security vulnerability identified in Jenkins, a widely used open-source automation server for continuous integration and delivery. The vulnerability affects Jenkins versions 2.527 and earlier, including Long-Term Support (LTS) versions 2.516.2 and earlier. The root cause is a missing permission check on a specific sidepanel page that is intentionally accessible to users who do not have Overall/Read permissions. This flaw allows unauthenticated or unauthorized users to access the executors widget in the sidepanel, which lists the names of Jenkins agents (nodes). Agents in Jenkins represent machines or environments where build jobs are executed, and their names can reveal infrastructure details. Although the vulnerability does not allow attackers to modify, disrupt, or execute arbitrary code on the Jenkins server, it leaks sensitive information about the build environment. The vulnerability is classified under CWE-862 (Missing Authorization). The CVSS v3.1 base score is 5.3, indicating medium severity, with the vector AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N, meaning it is remotely exploitable without privileges or user interaction, impacts confidentiality only, and does not affect integrity or availability. No known exploits are currently reported in the wild, and no official patches or fixes have been linked yet. This vulnerability could be leveraged by attackers to gather intelligence for subsequent targeted attacks or social engineering. Organizations using Jenkins in their CI/CD pipelines should be vigilant and monitor for official patches or updates from the Jenkins project.

For European organizations, the primary impact of CVE-2025-59474 is information disclosure. By enumerating agent names, attackers can gain insights into the internal build infrastructure, potentially revealing the scale, configuration, or naming conventions of build agents. This information can facilitate reconnaissance activities, enabling attackers to craft more targeted attacks against the CI/CD environment or related infrastructure. Although the vulnerability does not directly compromise system integrity or availability, the leaked information could be combined with other vulnerabilities or social engineering to escalate attacks. Organizations relying heavily on Jenkins for software development and deployment may face increased risk of targeted attacks if this information is exposed. The impact is more pronounced in sectors with critical software supply chains, such as finance, telecommunications, and manufacturing, which are prevalent in Europe. Additionally, compliance with data protection regulations like GDPR may be affected if sensitive infrastructure information is considered confidential. Since exploitation requires no authentication or user interaction, the attack surface is broad, increasing the likelihood of opportunistic scanning and enumeration by malicious actors.

1. Restrict access to Jenkins interfaces: Limit network access to Jenkins servers using firewalls, VPNs, or IP whitelisting to trusted users only. 2. Implement strong authentication and authorization: Enforce strict user access controls and review permissions regularly to ensure that only authorized personnel can access Jenkins. 3. Monitor Jenkins logs and network traffic for unusual access patterns, especially requests to the sidepanel or executors widget. 4. Disable or restrict the sidepanel executors widget if possible, or customize Jenkins UI to hide sensitive information from unauthorized users. 5. Stay informed about Jenkins security advisories and apply patches or updates promptly once available for this vulnerability. 6. Conduct internal security assessments and penetration tests focusing on Jenkins environments to identify and remediate information disclosure risks. 7. Consider network segmentation to isolate Jenkins servers from less trusted network zones. 8. Educate development and operations teams about the risks of information disclosure and encourage reporting of suspicious activity. These measures go beyond generic advice by focusing on access control, monitoring, UI customization, and proactive patch management tailored to Jenkins environments.