Digest.pm < 1.17 has vul.
https://metacpan.org/source/GAAS/Digest-1.17/Changes
Normally, you don't need to pass the digesting algorithm for Digest.pm.
This issue is not a big issue.
Older version of Digest.pm runs any perl code in Digest->new
Digest->new("strict; `rm -rf /`");If you passing user's input to Digest.pm, you need to update the module.
ref.