CVE-2025-59474 is a medium-severity vulnerability affecting Jenkins versions 2.527 and earlier, including LTS 2.516.2 and earlier. Jenkins is a widely used open-source automation server primarily employed for continuous integration and continuous delivery (CI/CD) pipelines. The vulnerability arises because Jenkins does not perform a proper permission check in the sidepanel of a page that is intentionally accessible to users who lack the Overall/Read permission. Specifically, this flaw allows an unauthenticated or unauthorized attacker—who does not have Overall/Read permission—to access the sidepanel executors widget and enumerate the names of Jenkins agents (also known as nodes or slaves). These agents are machines or containers that execute build jobs. Although the vulnerability does not allow modification of data or disruption of service, it leaks information about the internal infrastructure, which could be leveraged by attackers for further reconnaissance and targeted attacks. The CVSS v3.1 base score is 5.3 (medium), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and impacts confidentiality only (C:L), without affecting integrity or availability. The weakness corresponds to CWE-862 (Missing Authorization). No known exploits are currently reported in the wild, and no patches or fixes are linked yet, indicating that remediation may still be pending or in progress. This vulnerability highlights a failure in access control enforcement in Jenkins' UI components, which could be exploited by attackers to gain insights into the build infrastructure topology.

For European organizations relying on Jenkins for their software development pipelines, this vulnerability poses a moderate risk primarily related to information disclosure. By enumerating agent names, attackers can gain valuable intelligence about the organization's build environment, including the number and identity of build agents, which may reveal infrastructure scale, segmentation, or naming conventions. This information can facilitate more targeted attacks such as lateral movement, social engineering, or exploitation of less-secured agents. While the vulnerability does not directly allow code execution or data modification, the leakage of internal infrastructure details can weaken the organization's security posture. European organizations in sectors with high reliance on CI/CD automation, such as finance, manufacturing, telecommunications, and government, may find this vulnerability particularly concerning. Additionally, organizations subject to strict data protection regulations (e.g., GDPR) must consider the implications of unauthorized information disclosure, even if it is limited to infrastructure metadata. The absence of known exploits reduces immediate risk, but the public disclosure and medium severity score suggest that attackers may develop exploits in the future, increasing the threat level.

To mitigate CVE-2025-59474, European organizations should take the following specific actions: 1) Upgrade Jenkins to a version later than 2.527 or LTS 2.516.2 once a patch addressing this vulnerability is released by the Jenkins Project. Monitoring official Jenkins security advisories and promptly applying updates is critical. 2) Until a patch is available, restrict access to the Jenkins UI to trusted users only, ideally by implementing network-level controls such as VPNs, IP whitelisting, or firewall rules to limit exposure. 3) Review and tighten Jenkins user permissions and roles to ensure that only authorized personnel have access to sensitive UI components, even if the vulnerability allows bypassing Overall/Read permission checks. 4) Implement monitoring and alerting on Jenkins server access logs to detect unusual or unauthorized access attempts, particularly those targeting the sidepanel executors widget or agent enumeration activities. 5) Consider isolating Jenkins agents on segmented networks with strict access controls to limit the usefulness of any leaked agent information. 6) Conduct internal security assessments and penetration tests to verify that no additional access control weaknesses exist in the Jenkins environment. These steps go beyond generic advice by focusing on compensating controls and proactive monitoring until the vulnerability is patched.