CVE-2026-55156: Token Optimizer MCP: Unauthenticated Path Traversal in Dashboard Session Log API Endpoints

The dashboard HTTP server in token-optimizer-mcp exposes /api/session-summary and /api/session-events with no authentication middleware — any network-accessible client can reach them without credentials. Both handlers concatenate the caller-supplied sessionId query parameter directly into a filesystem path via path.join, and Node.js normalizes .. segments at resolution time, allowing an unauthenticated attacker to read any .jsonl file reachable from the server’s filesystem. Successful reproduction confirmed exfiltration of a .jsonl file located outside the intended hooksDataPath directory with a single unauthenticated HTTP GET request.