diff --git a/lib/metasploit/framework/credential.rb b/lib/metasploit/framework/credential.rb
index 108463fb24..9ec1a428ff 100644
--- a/lib/metasploit/framework/credential.rb
+++ b/lib/metasploit/framework/credential.rb
@@ -48,7 +48,8 @@ module Metasploit
       # These values should be #demodularized from subclasses of
       # `Metasploit::Credential::Private`
       validates :private_type,
-        inclusion: { in: [ :password, :ntlm_hash, :ssh_key ] }
+        inclusion: { in: [ :password, :ntlm_hash, :ssh_key ] },
+        if: "private_type.present?"
 
       # If we have no private we MUST have a public
       validates :public,