CVE-2025-11539 is a critical vulnerability classified under CWE-94 (Improper Control of Generation of Code), affecting Grafana Image Renderer versions from 1.0.0 through 4.0.16. The vulnerability stems from an arbitrary file write issue in the /render/csv HTTP endpoint, where the filePath parameter is not properly validated. This flaw allows an attacker to write a malicious shared object file to an arbitrary location on the host system. The Grafana Image Renderer uses Chromium to render images, and the malicious shared object is subsequently loaded by the Chromium process, resulting in remote code execution (RCE). Exploitation requires the attacker to have knowledge of the default or otherwise compromised authentication token (authToken) and network access to the image renderer endpoint. The CVSS v3.1 base score is 9.9, indicating critical severity with network attack vector, low attack complexity, requiring privileges but no user interaction, and complete impact on confidentiality, integrity, and availability. The vulnerability is particularly dangerous because it allows attackers to execute arbitrary code remotely, potentially leading to full system compromise. No public exploits have been reported yet, but the high severity and ease of exploitation make it a significant threat. The vulnerability affects all deployments using the vulnerable versions with default or known tokens and exposed endpoints, emphasizing the need for immediate remediation.

For European organizations, this vulnerability poses a critical risk, especially for those relying on Grafana for monitoring and visualization in their IT infrastructure. Successful exploitation can lead to full system compromise, data theft, disruption of monitoring services, and lateral movement within networks. Confidentiality is at risk as attackers can execute arbitrary code to access sensitive data. Integrity and availability are also severely impacted, as attackers can manipulate or disable monitoring systems, potentially masking other malicious activities or causing operational outages. Organizations in sectors such as finance, healthcare, energy, and government, which often use Grafana for critical infrastructure monitoring, could face severe operational and reputational damage. Additionally, compliance with GDPR and other data protection regulations may be jeopardized if personal or sensitive data is exposed or systems are disrupted. The requirement for the attacker to know or guess the default token means that organizations with weak token management or exposed endpoints are particularly vulnerable. The lack of known exploits in the wild currently provides a small window for proactive defense, but the critical nature demands urgent attention.

1. Immediately change the default authToken used by the Grafana Image Renderer 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 to limit exposure only to trusted systems. 3. Monitor access logs for unusual or unauthorized attempts to access the image renderer endpoint, focusing on attempts to use the default or weak tokens. 4. Apply patches or updates from Grafana as soon as they become available; if no patch is currently available, consider disabling the image renderer service or the vulnerable endpoint temporarily. 5. Conduct a thorough audit of all Grafana deployments to identify and remediate any instances running vulnerable versions. 6. Implement runtime application self-protection (RASP) or endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of exploitation attempts. 7. Educate administrators and DevOps teams on the importance of secure token management and endpoint exposure minimization. 8. Use network intrusion detection systems (NIDS) to detect potential exploitation attempts targeting this vulnerability. 9. Consider deploying Web Application Firewalls (WAFs) with custom rules to block suspicious requests to the /render/csv endpoint. 10. Regularly review and update incident response plans to include scenarios involving Grafana compromise.