This vulnerability (CVE-2026-15583) in Grafana MCP Server is caused by a confused-deputy flaw that allows an unauthenticated remote attacker to supply a specially crafted X-Grafana-URL header. This enables the attacker to exfiltrate the Grafana service-account token configured in the server's environment. Additionally, the flaw allows SSRF attacks targeting arbitrary internal services, including sensitive cloud metadata endpoints. The vulnerability has a CVSS v3.1 score of 8.6, indicating high severity, with network attack vector, low attack complexity, no privileges required, no user interaction, and a scope change. The impact is high confidentiality loss but no integrity or availability impact. There is no vendor advisory or patch available at this time, and no known exploits in the wild have been reported.

An attacker can remotely and without authentication obtain the Grafana service-account token from the server environment, leading to high confidentiality impact. This token exfiltration can facilitate further unauthorized access. The vulnerability also enables SSRF attacks against internal services, including cloud metadata endpoints, potentially exposing sensitive internal resources. There is no reported impact on integrity or availability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, monitor vendor communications for updates. No vendor-provided mitigation or temporary fix is currently documented.