ClamAV : freshclam hangs and uses 100% CPU
When there is a huge daily.cdiff file, the update process might take a long time to finish.
Sometimes, it is faster to delete the old daily definitions and re-downloading them.
sudo rm /var/lib/clamav/daily.cld
sudo freshclam
There was a large Cdiff published for older users recently. Try deleting the daily and daily cdiffs* and re-running Freshclam. Let me know if that works.