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.
Exploitability
AV:NAC:LAu:NImpact
C:PI:NA:N5/AV:N/AC:L/Au:N/C:P/I:N/A:N