diff --git a/gems/bundled_gems b/gems/bundled_gems
index 98266d6e58..b7ff849447 100644
--- a/gems/bundled_gems
+++ b/gems/bundled_gems
@@ -8,7 +8,7 @@ rss 0.2.9 https://github.com/ruby/rss 0.2.9
 net-ftp 0.1.3 https://github.com/ruby/net-ftp
 net-imap 0.2.2 https://github.com/ruby/net-imap
 net-pop 0.1.1 https://github.com/ruby/net-pop
-net-smtp 0.3.0 https://github.com/ruby/net-smtp
+net-smtp 0.3.1 https://github.com/ruby/net-smtp
 matrix 0.4.2 https://github.com/ruby/matrix
 prime 0.1.2 https://github.com/ruby/prime
 rbs 1.8.0 https://github.com/ruby/rbs