Crypt::DSA versions before 1.21 for Perl reused the nonce across signatures, leading to private-key recovery.
Crypt::DSA::sign caches the per-signature nonce material in the Key object without ever clearing it.
The first sign() on a Key object picks a nonce, and every later sign() on that same object reuses it, producing an identical "r".
Keys used to sign more than once with an affected version should be considered compromised.
Upgrade to version 1.21
Revoke any keys that may have been compromised.
Crypt::DSA was deprecated in version 1.20. You should migrate to another solution.