CVE-2013-2257

Cryptocat before 2.0.42 has Group Chat ECC Private Key Generation Brute Force Weakness...

CVE-2016-1000343

In the Bouncy Castle JCE Provider version 1.55 and earlier the DSA key pair generator generates a weak private key if used with default values. If the JCA key pair generator is not explicitly initialised with DSA parameters, 1.55 and earlier generates a private value assuming a 1024 bit key size...

kgpg uncrypted private key

Passphrase not used if keys are generated through wizard...

Signed content spoofing in ECDSA

Standard allows to generate private key in a way it will produce same signature for 2 different documents...