Since Perl 5.8, scalars can be used as file buffers. This is useful if your CSV modules requires a file handle. (I used Text::CSV which does not.)

use Text::CSV qw( );

my $content = ...;

my $csv = Text::CSV->new();
open my $csv_fh, '<', \$content;
while (<$csv_fh>) {
   my $status = $csv->parse($_)
      or die;
   my @fields = $csv->fields();
   ...
}
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If you don't require a file handle, it's simple to extract lines yourself.

use Text::CSV qw( );

my $content = ...;

my $csv = Text::CSV->new();
while (length($content)) {
   my ($line) = $content =~ s/^([^\r\n]*)\r?\n?//;
   my $status = $csv->parse($line)
      or die;
   my @fields = $csv->fields();
   ...
}
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Update: Added second snippet. Allowed for \r\n.