CVE-2025-64136 is a cross-site request forgery (CSRF) vulnerability identified in the Jenkins Themis Plugin version 1.4.1 and earlier. The vulnerability allows an attacker to craft malicious web requests that, when executed by an authenticated Jenkins user, cause the Jenkins server to connect to an attacker-specified HTTP server. This behavior can be exploited to perform server-side request forgery (SSRF)-like actions, potentially exposing internal network resources or enabling further attacks such as information gathering or pivoting within the network. The vulnerability arises because the plugin does not adequately verify the origin of requests, allowing unauthorized commands to be executed via forged requests. The CVSS 3.1 base score is 4.3 (medium), reflecting that the attack vector is network-based, requires no privileges, but does require user interaction (the user must visit a malicious page). The impact is limited to integrity, as the attacker can influence the Jenkins server's outbound connections but cannot directly compromise confidentiality or availability. No patches or exploit code are currently publicly available, and no known exploits have been reported in the wild. The vulnerability is categorized under CWE-352 (Cross-Site Request Forgery).

For European organizations, the impact of CVE-2025-64136 primarily concerns the integrity of Jenkins CI/CD environments. An attacker could leverage this vulnerability to induce Jenkins servers to connect to malicious endpoints, potentially exposing internal network topology or services that are otherwise inaccessible externally. This could facilitate reconnaissance or lateral movement within corporate networks. While the vulnerability does not directly compromise confidentiality or availability, the induced connections could be used as a stepping stone for more complex attacks. Organizations heavily reliant on Jenkins for software development and deployment, especially those integrating the Themis Plugin, face increased risk. The requirement for user interaction means social engineering or phishing campaigns could be used to trigger exploitation. Given the widespread use of Jenkins in European tech sectors, this vulnerability could affect critical infrastructure, financial institutions, and technology companies. However, the absence of known exploits and the medium severity rating suggest the immediate risk is moderate but warrants timely remediation.

To mitigate CVE-2025-64136, European organizations should: 1) Upgrade the Jenkins Themis Plugin to a version that addresses this vulnerability once available; if no patch exists, consider disabling or uninstalling the plugin if it is not essential. 2) Implement strict CSRF protections at the Jenkins server level, including enabling Jenkins' built-in CSRF protection mechanisms and validating request origins. 3) Restrict access to Jenkins interfaces to trusted networks and users, minimizing exposure to untrusted or external users who could trigger malicious requests. 4) Monitor outbound network traffic from Jenkins servers for unusual or unauthorized connections to external HTTP servers, which could indicate exploitation attempts. 5) Educate users about the risks of interacting with untrusted web content while authenticated to Jenkins to reduce the likelihood of successful social engineering. 6) Employ network segmentation to limit the potential impact of SSRF-like behaviors induced by this vulnerability. 7) Regularly review plugin usage and permissions to ensure minimal attack surface. These steps go beyond generic advice by focusing on plugin-specific controls, network monitoring, and user awareness tailored to the Jenkins environment.