CVE-2025-64138 is a CSRF vulnerability identified in the Jenkins Start Windocks Containers Plugin version 1.4 and earlier. Jenkins is a widely used automation server for continuous integration and delivery, and the Start Windocks Containers Plugin facilitates the management and launching of Windows container instances via Windocks technology. The vulnerability arises because the plugin fails to properly validate the authenticity of requests that trigger connections to URLs specified by users. An attacker can exploit this by crafting a malicious web page that, when visited by an authenticated Jenkins user, causes the plugin to connect to an attacker-controlled URL without the user's consent. This can lead to unauthorized actions such as data leakage, command execution in the context of the Jenkins server, or manipulation of containerized environments. The exploit does not require the attacker to have direct access to Jenkins credentials but relies on social engineering to induce the user to visit a malicious site. No CVSS score has been assigned yet, and no patches or mitigations have been officially released. The vulnerability is classified as a CSRF issue, which typically impacts the integrity and confidentiality of the system by enabling unauthorized commands to be executed under the victim's credentials. The absence of known exploits in the wild suggests it is a recently discovered issue. The plugin's versioning indicates that all versions up to 1.4 are affected, and users should consider this in their risk assessments.

For European organizations, this vulnerability poses a risk primarily to the integrity and confidentiality of Jenkins-managed environments. Jenkins is heavily used in software development pipelines, including in critical sectors such as finance, manufacturing, and government services across Europe. Exploitation could allow attackers to manipulate container deployments, potentially injecting malicious code or exfiltrating sensitive build or deployment data. This could disrupt development workflows, compromise software supply chains, or lead to unauthorized access to internal systems. The impact is heightened in environments where Jenkins servers are exposed to internal users with broad privileges or where the plugin is used to manage critical containerized applications. Although availability impact is limited, the potential for unauthorized actions and data compromise makes this a significant concern. The lack of a patch increases exposure time, and organizations with less mature security controls around Jenkins are at greater risk. European entities with stringent data protection regulations (e.g., GDPR) may face compliance risks if sensitive data is exposed due to exploitation.

To mitigate this vulnerability, European organizations should immediately review and restrict access to Jenkins instances, especially those using the Start Windocks Containers Plugin. Implement strict CSRF protections at the Jenkins server level, including enabling built-in CSRF protection features and validating all incoming requests. Limit plugin usage to trusted users and consider disabling or uninstalling the plugin if it is not essential. Monitor Jenkins logs for unusual or unexpected connections initiated by the plugin. Employ network segmentation to isolate Jenkins servers from sensitive internal resources and restrict outbound connections from Jenkins to only trusted URLs. Educate users about the risks of visiting untrusted websites while authenticated to Jenkins. Until an official patch is released, consider deploying web application firewalls (WAFs) or reverse proxies to detect and block suspicious CSRF attempts targeting Jenkins endpoints. Regularly check for updates from the Jenkins project and apply patches promptly once available.