CVE-2025-32916 identifies a vulnerability in Checkmk, a widely used IT infrastructure monitoring software developed by Checkmk GmbH. The issue arises from the use of the HTTP GET method to transmit sensitive form data within URL query parameters in versions prior to 2.4.0p13, 2.3.0p38, and 2.2.0p46, including the end-of-life 2.1.0 version. Using GET requests for sensitive data is problematic because URLs are commonly logged in browser histories, web server logs, proxy logs, and network monitoring tools, potentially exposing confidential information to unauthorized viewers. The vulnerability is classified under CWE-598, which relates to the unsafe use of GET requests with sensitive query strings. The CVSS 4.0 score is 1.0 (low), reflecting limited impact due to the requirement for authenticated access (PR:H), partial user interaction (UI:P), and local attack vector (AV:L). The vulnerability does not affect integrity or availability but poses a confidentiality risk (VC:L). No public exploits are known, and the vendor has reserved the CVE since April 2025, with the vulnerability published in October 2025. The affected versions are commonly deployed in enterprise environments for monitoring critical IT infrastructure, making the confidentiality risk relevant if logs or histories are accessed by unauthorized personnel.

For European organizations, the primary impact of this vulnerability is the potential exposure of sensitive information such as credentials, tokens, or configuration data through URL query strings. This exposure could occur if browser histories, web server logs, or network traffic are accessed by malicious insiders or external attackers who have gained some level of access. Although exploitation requires authenticated access and some user interaction, the risk remains significant in environments with shared workstations, insufficient log access controls, or compromised user accounts. Confidentiality breaches could lead to further attacks, including lateral movement or privilege escalation. Given that Checkmk is often used in critical infrastructure monitoring, any leakage of sensitive monitoring data could indirectly impact operational security. However, the low CVSS score and lack of known exploits suggest the immediate threat level is low. Organizations relying on older Checkmk versions should consider the risk in the context of their internal security posture and data sensitivity.

1. Upgrade affected Checkmk installations to the latest patched versions (2.4.0p13, 2.3.0p38, 2.2.0p46, or later) as soon as possible to eliminate the vulnerability. 2. Review and audit web server and proxy logs to ensure sensitive data is not inadvertently stored in URL query strings. 3. Implement strict access controls on logs and browser histories to prevent unauthorized access. 4. Educate users and administrators about the risks of transmitting sensitive data via GET requests and encourage the use of POST methods or other secure transmission mechanisms. 5. Monitor network traffic for unusual access patterns that might indicate attempts to capture URL data. 6. If upgrading is not immediately feasible, consider deploying web application firewalls or reverse proxies that can rewrite or block sensitive query parameters. 7. Regularly review Checkmk configuration and custom scripts to avoid embedding sensitive information in URLs. 8. Conduct internal penetration testing focusing on information leakage through logs and histories.