CVE-2026-15583 is a vulnerability in Grafana MCP Server caused by a confused-deputy flaw. It allows an unauthenticated remote attacker to exfiltrate the Grafana service-account token configured in the server environment by supplying a specially crafted X-Grafana-URL request header. This token exposure can lead to unauthorized access. Additionally, the vulnerability enables SSRF attacks targeting arbitrary internal services, including sensitive cloud metadata endpoints, potentially allowing further internal network reconnaissance or exploitation. The vulnerability is rated with a CVSS 3.1 score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N), reflecting high confidentiality impact with no required privileges or user interaction. No vendor advisory or patch information is currently available, and the affected version is =0.0.0.

The vulnerability allows unauthenticated remote attackers to exfiltrate sensitive service-account tokens from the Grafana MCP Server environment, leading to a complete confidentiality breach of these credentials. This can facilitate unauthorized access to Grafana services. Furthermore, the SSRF capability enables attackers to interact with internal services, including cloud metadata endpoints, which may lead to further internal network compromise or information disclosure. There is no impact on integrity or availability reported.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict network access to the Grafana MCP Server to trusted sources only and monitor for suspicious requests involving the X-Grafana-URL header. Avoid exposing the server to untrusted networks. Follow vendor communications closely for updates on patches or official mitigations.