GHSA-73hc-m4hx-79pj mcp-memory-service Vulnerable to System Information Disclosure via Health Endpoint

• PyPI mcp-memory-service: < 10.21.0 → fixed in 10.21.0

Summary The `/api/health/detailed` endpoint returns detailed system information including OS version, Python version, CPU count, memory totals, disk usage, and the full database filesystem path. When `MCP_ALLOW_ANONYMOUS_ACCESS=true` is set (required for the HTTP server to function without OAuth/API key), this endpoint is accessible without authentication. Combined with the default `0.0.0.0` binding, this exposes sensitive reconnaissance data to the entire network. Details Vulnerable Code `health.py:90-101` - System information collection ```python system_info = { "platform": platform.system(), # e.g., "Linux", "Darwin" "platform_version": platform.version(), # Full OS kernel version string "python_version": platform.python_version(),# e.g., "3.12.1" "cpu_count": psutil.cpu_count(), # CPU core count "memory_total_gb": round(memory_info.total / (10243), 2), "memory_available_gb": round(memory_info.available / (10243), 2), "memory_percent": memory_info.percent, "disk_total_gb": round(disk_info.total / (10243), 2), "disk_free_gb": round(disk_info.free / (10243), 2), "disk_percent": round((disk_info.used / disk_info.total) * 100, 2) } ``` `health.py:131-132` - Database path disclosure ```python if hasattr(storage, 'db_path'): storage_info["database_path"] = storage.db_path # Full filesystem path ``` Authentication Bypass Path The `/api/health/detailed` endpoint uses `require_read_access` which calls `get_current_user`. When `MCP_ALLOW_ANONYMOUS_ACCESS=true`, the auth middleware grants access: ```python middleware.py:372-379 if ALLOW_ANONYMOUS_ACCESS: logger.debug("Anonymous access explicitly enabled, granting read-only access") return AuthenticationResult( authenticated=True, client_id="anonymous", scope="read", auth_method="none" ) ``` Note: The basic `/health` endpoint (line 68) has no auth dependency at all and returns version and uptime information unconditionally. Information Exposed | Field | Example Value | Reconnaissance Value | |-------|--------------|---------------------| | `platform` | `"Linux"` | OS fingerprinting | | `platform_version` | `"#1 SMP PREEMPT_DYNAMIC..."` | Kernel version → CVE targeting | | `python_version` | `"3.12.1"` | Python CVE targeting | | `cpu_count` | `8` | Resource enumeration | | `memory_total_gb` | `32.0` | Infrastructure profiling | | `database_path` | `"/home/user/.mcp-memory/memories.db"` | Username + file path disclosure | | `database_size_mb` | `45.2` | Data volume estimation | Attack Scenario 1. Attacker scans the local network for services on port 8000 2. Finds mcp-memory-service with HTTP enabled and anonymous access 3. Calls `GET /api/health/detailed` (no credentials needed) 4. Receives OS version, Python version, full database path (revealing username), system resources 5. Uses this information to: • Target known CVEs for the specific OS/Python version • Identify the database file location for potential direct access • Profile the system for further attacks PoC ```python Show the system info that would be exposed import platform, psutil system_info = { "platform": platform.system(), "platform_version": platform.version(), "python_version": platform.python_version(), "cpu_count": psutil.cpu_count(), "memory_total_gb": round(psutil.virtual_memory().total / (10243), 2), } print(system_info) # All of this is returned to unauthenticated users ``` Impact • OS fingerprinting: Exact OS and kernel version enables targeted exploit selection • Path disclosure: Database path reveals username, home directory structure, and file locations • Resource enumeration: CPU, memory, and disk info reveal infrastructure scale • Reconnaissance enablement: Combined information significantly reduces attacker effort for follow-up attacks Remediation 1. Remove system details from default health endpoint - return only `status`, `version`, `uptime`: ```python @router.get("/health/detailed") async def detailed_health_check( storage: MemoryStorage = Depends(get_storage), user: AuthenticationResult = Depends(require_write_access) # Require admin/write access ): # Only return storage stats, not system info ... ``` 2. Do not expose `database_path` - this leaks the filesystem structure: ```python Remove or redact storage_info["database_path"] = storage.db_path # REMOVE THIS ``` 3. Add auth to basic `/health` or limit it to status-only (no version): ```python @router.get("/health") async def health_check(): return {"status": "healthy"} # No version, no uptime ``` Alternatively, Bind to `127.0.0.1` by default** instead of `0.0.0.0`, preventing network-based reconnaissance entirely: ```python In config.py — change default from '0.0.0.0' to '127.0.0.1' HTTP_HOST = os.getenv('MCP_HTTP_HOST', '127.0.0.1') ``` Users who need network access can explicitly set `MCP_HTTP_HOST=0.0.0.0`, making the exposure a conscious opt-in rather than a default.