CurlFtpFs is old and unsupported. It can't even copy files with a "#" in the filename.
https://alternativeto.net/software/curlftpfs/about/ says it has been obsoleted by LUFS, but LUFS seems to be even older (2003)!
Is there anything better?
I found AVFS, but I am not sure it is usable with Vifm. There are some old instructions for rox though.
See this question for example of using AVFS for viewing archives, not sure how well it applies for remote mounts though.