CVE-2025-11539
📋 TL;DR
Grafana Image Renderer versions 1.0.0 through 4.0.16 contain an arbitrary file write vulnerability in the /render/csv endpoint that allows remote code execution. Attackers can write malicious shared objects to arbitrary locations that are then loaded by Chromium. Organizations using vulnerable versions with default authentication tokens or exposed endpoints are affected.
💻 Affected Systems
- grafana-image-renderer
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining root/system privileges, data exfiltration, ransomware deployment, and persistent backdoor installation.
Likely Case
Server compromise leading to data theft, service disruption, and lateral movement within the network.
If Mitigated
Attack blocked at network perimeter or authentication layer with minimal impact.
🎯 Exploit Status
Exploitation requires authentication token but default token is commonly used. Attack chain is straightforward once token is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.0.17
Vendor Advisory: https://grafana.com/security/security-advisories/cve-2025-11539/
Restart Required: Yes
Instructions:
1. Update grafana-image-renderer to version 4.0.17 or later. 2. Restart the grafana-image-renderer service. 3. Verify the update was successful.
🔧 Temporary Workarounds
Change Default Authentication Token
allReplace the default 'authToken' with a strong, unique token to prevent unauthorized access.
Edit configuration file and set GF_RENDERER_AUTH_TOKEN to a strong random value
Network Segmentation
allRestrict network access to grafana-image-renderer endpoints to only trusted sources.
Use firewall rules to limit access to renderer service ports
🧯 If You Can't Patch
- Implement strict network access controls to isolate grafana-image-renderer from untrusted networks
- Change authentication token immediately and monitor for unauthorized access attempts
🔍 How to Verify
Check if Vulnerable:
Check grafana-image-renderer version and verify it's between 1.0.0 and 4.0.16 inclusive.Check Version:
grafana-image-renderer --version or check package manager (apt list --installed | grep grafana-image-renderer)Verify Fix Applied:
Confirm version is 4.0.17 or higher and test that /render/csv endpoint properly validates filePath parameter.📡 Detection & Monitoring
Log Indicators:
- Unusual file write operations in renderer logs
- Multiple failed authentication attempts to renderer endpoint
- Unexpected process execution from renderer service
Network Indicators:
- Unusual outbound connections from renderer service
- Traffic to renderer endpoint from unexpected sources
SIEM Query:
source="grafana-image-renderer" AND (file_write OR unauthorized_access OR process_execution)