In software.c, system_sw_os() opens HKEY via open_registry_info_key() before validating the first parameter. For an unknown value, the function returns right away and never calls RegCloseKey(), so one registry handle leaks on every check

	if (NULL == (handle = open_registry_info_key()))
	...
	else
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Invalid first parameter."));
		return ret;		/* RegCloseKey(handle) at "out:" is skipped */
	}
	...
out:
	RegCloseKey(handle);