The JSON gem before 1.5.5, 1.6.x before 1.6.8, and 1.7.x before 1.7.7 for Ruby allows remote attackers to cause a denial of service (resource consumption) or bypass the mass assignment protection mechanism via a crafted JSON document that triggers the creation of arbitrary Ruby symbols or certain internal objects, as demonstrated by conducting a SQL injection attack against Ruby on Rails, aka "Unsafe Object Creation Vulnerability."
Directory traversal vulnerability in lib/mail/network/delivery_methods/file_delivery.rb in the Mail gem before 2.4.4 for Ruby allows remote attackers to read arbitrary files via a .. (dot dot) in the to parameter.
The Mail gem before 2.4.3 for Ruby allows remote attackers to execute arbitrary commands via shell metacharacters in a (1) sendmail or (2) exim delivery.