Full Report
Grafana security advisory (AV26-710)
Analysis Summary
# Vulnerability: Grafana SSRF and Unbounded Memory Allocation
## CVE Details
- **CVE ID:** CVE-2026-15583
- **CVSS Score:** Not explicitly listed in advisory summary (Estimated High)
- **CWE:** CWE-918 (Server-Side Request Forgery)
- **CVE ID:** CVE-2026-21729
- **CVSS Score:** Not explicitly listed in advisory summary (Estimated Medium/High)
- **CWE:** CWE-770 (Allocation of Resources Without Limits or Throttling)
## Affected Systems
- **Products:** Grafana MCP Server, Grafana Loki
- **Versions:**
- Grafana MCP Server: Version 0.17.1 and prior
- Grafana Loki: Version 3.7.0 and prior
- **Configurations:** Systems utilizing the `X-Grafana-URL` header in MCP or the `detected_fields` query feature in Loki.
## Vulnerability Description
1. **CVE-2026-15583 (Grafana MCP Server):** A Server-Side Request Forgery (SSRF) vulnerability exists where the server improperly handles the `X-Grafana-URL` header. An attacker can manipulate this header to force the MCP server to make requests to unintended internal or external resource locations.
2. **CVE-2026-21729 (Grafana Loki):** A resource management flaw occurs when processing `detected_fields` queries. The system fails to impose proper limits on the results, leading to unbounded memory allocation. This can result in a Denial of Service (DoS) by exhausting system memory.
## Exploitation
- **Status:** Not specified as exploited in the wild; PoC status not confirmed in the brief.
- **Complexity:** Low to Medium
- **Attack Vector:** Network
## Impact
- **Confidentiality:** High (Internal network scanning and information disclosure via SSRF)
- **Integrity:** Low
- **Availability:** High (System crash or service unavailability via memory exhaustion)
## Remediation
### Patches
The Cyber Centre recommends upgrading to the following versions (or later):
- **Grafana MCP Server:** Update to versions beyond 0.17.1.
- **Grafana Loki:** Update to versions beyond 3.7.0.
### Workarounds
- **For Loki:** Restrict the use of `detected_fields` in queries through policy or configuration if an immediate update is not possible.
- **For MCP:** Implement network-level egress filtering to prevent the MCP server from reaching sensitive internal metadata services or unauthorized external IPs.
## Detection
- **Indicators of Compromise:** Unusual internal network traffic originating from the Grafana MCP server; spike in memory usage on Loki nodes correlating with `detected_fields` query execution.
- **Detection methods:** Review HTTP logs for unauthorized `X-Grafana-URL` header values; monitor Grafana Loki resource consumption metrics (Resident Set Size).
## References
- [Grafana Security Advisory CVE-2026-15583] hxxps[://]grafana[.]com/security/security-advisories/cve-2026-15583/
- [Grafana Security Advisory CVE-2026-21729] hxxps[://]grafana[.]com/security/security-advisories/cve-2026-21729/
- [Grafana Blog] hxxps[://]grafana[.]com/blog/