From my knowledge there is no existing toolbox to manage this CDF format. However conversion tools exists  that can convert CDF to HDF4 and HDF4 to HDF5 (natively supported by Scilab) ; IMHO this will be the simpler way to handle that
You could also :
use SWIG to create your own toolbox mapping the C API to Scilab
the CDFj package to call CDF function using Java from Scilab (there might be some dataset copies)
From: users <[hidden email]> On Behalf Of
P M Sent: Wednesday, February 10, 2021 7:19 PM To: International users mailing list for Scilab. <[hidden email]> Subject: [Scilab-users] Scilab & cdf-file format
Is there any Scilab toolbox available, handling the cdf-file-format?
There is a toolbox for 5.5.2 called scinetcdf which will work - this will
work with the standard netCDF format. However, it will not work in version
6.x of Scilab. Perhaps a Scilab expert could look at how to get it compiled
for the latest Scilab?