CVE-2025-11539 is a critical vulnerability in the Grafana Image Renderer component, specifically affecting versions from 1.0.0 through 4.0.16. The root cause is an arbitrary file write vulnerability due to lack of validation on the filePath parameter in the /render/csv HTTP endpoint. This flaw allows an attacker with knowledge of the default or leaked authentication token (authToken) and network access to the image renderer endpoint to write a malicious shared object (.so) file to an arbitrary location on the host system. The Chromium process used by the renderer then loads this malicious shared object, enabling remote code execution (RCE) with the privileges of the renderer process. The vulnerability is classified under CWE-94 (Improper Control of Generation of Code), indicating that untrusted input is used to generate or execute code. The CVSS 3.1 base score is 9.9, reflecting network attack vector, low attack complexity, required privileges (authToken), no user interaction, and complete compromise of confidentiality, integrity, and availability with scope change. Although no exploits have been publicly observed in the wild yet, the vulnerability’s characteristics make it highly exploitable. The flaw affects Grafana deployments that have not changed the default authToken or where the token is otherwise compromised, and where the image renderer endpoint is reachable by attackers, such as in misconfigured or exposed environments. This vulnerability poses a severe risk to organizations relying on Grafana for monitoring and visualization, especially where the image renderer is exposed to untrusted networks or users. Immediate mitigation and patching are critical to prevent potential exploitation.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Grafana in IT infrastructure monitoring, industrial control systems, and cloud environments. Successful exploitation could lead to full system compromise, allowing attackers to execute arbitrary code, steal sensitive data, disrupt monitoring services, or pivot within networks. This can impact confidentiality by exposing sensitive operational data, integrity by allowing tampering with monitoring outputs or system files, and availability by causing service outages or denial of service. Critical sectors such as finance, energy, manufacturing, and government entities in Europe that rely on Grafana for real-time monitoring are particularly vulnerable. The ability to remotely execute code without user interaction and with low complexity increases the likelihood of targeted attacks or automated exploitation attempts. The compromise of monitoring infrastructure can also blind defenders to ongoing attacks, exacerbating incident response challenges. Given the criticality of monitoring systems, the impact extends beyond IT to operational technology environments, potentially affecting physical processes and safety.

European organizations should immediately verify if they are running affected versions of grafana-image-renderer (1.0.0 through 4.0.16). If so, they should: 1) Change the default authToken to a strong, unique token to prevent unauthorized access. 2) Restrict network access to the /render/csv endpoint by implementing firewall rules, network segmentation, or VPN access controls to limit exposure to trusted users only. 3) Monitor logs for suspicious access attempts to the image renderer endpoint and anomalous file writes. 4) Disable or isolate the image renderer service if it is not essential to operations until a patched version is available. 5) Apply patches or upgrade to a fixed version as soon as the vendor releases one. 6) Employ runtime application self-protection (RASP) or endpoint detection and response (EDR) tools to detect abnormal process behavior related to Chromium or shared object loading. 7) Conduct a thorough review of Grafana deployment configurations to ensure no other default credentials or insecure endpoints are exposed. These steps go beyond generic advice by focusing on access control, token management, and active monitoring specific to this vulnerability’s exploitation vector.