Ground Station: Unauthenticated arbitrary file write (path traversal) in save-waterfall-snapshot leads to remote code execution

Ground Station is a browser-based suite for satellite tracking, SDR reception, hardware control, and telemetry decoding. Prior to version 0.4.13, the unauthenticated save-waterfall-snapshot Socket.IO command passes attacker-controlled snapshotName input from backend/handlers/entities/sdr.py to backend/server/snapshots.py, where os.path.join permits an absolute path or parent-directory traversal and writes attacker-controlled base64-decoded bytes outside backend/data/snapshots. An attacker can write a logging YAML file containing a logging.config.dictConfig callable factory, use the unauthenticated update-app-config operation to set log_config to that file, and invoke restart_service. During restart, backend/common/logger.py passes the YAML through resolve_log_config_path(), yaml.safe_load(), and logging.config.dictConfig(), which executes the factory with service privileges and can also cause a persistent crash loop. This issue is fixed in version 0.4.13.