One way:

>perl -wMstrict -le
"my $s = 'xxx 293F:2945 yy ff:103 zz';
 ;;
 my @ranges =
   map { eval join '..',  map hex,  split /:/ }
   $s =~ m{ [[:xdigit:]]+ : [[:xdigit:]]+ }xmsg
   ;
 ;;
 printf q{%x }, $_ for @ranges;
"
293f 2940 2941 2942 2943 2944 2945 ff 100 101 102 103
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