What happened
Published August 2, 2026 (CVSS 7.5/High). ArcadeDB's MCP interface leaks a sensitive high-availability cluster authentication token through a routine settings-retrieval tool call, with no access-level gating on the sensitive field.
Why it matters
MCP tool surfaces are increasingly used by AI agents to introspect and manage backend databases; leaking cluster secrets through an ostensibly read-only "get settings" tool call lets any agent (or attacker abusing agent tool access) escalate to cluster-level impersonation, undermining the database's HA trust model.
Attack vector
The MCP `get_server_settings` tool exposes the `arcadedb.ha.clusterToken` in cleartext to any client with MCP access. An attacker with MCP-level access can retrieve the token and reuse it with the `X-ArcadeDB-Cluster-Token` and `X-ArcadeDB-Forwarded-User` headers to impersonate cluster nodes or forwarded users.
Affected systems
ArcadeDB < 26.7.3 (MCP get_server_settings tool)
Mitigation
Upgrade to ArcadeDB 26.7.3 or later; rotate the cluster HA token after upgrading. See GHSA-p9wc-4fhr-78wm.