diff --git a/NEWS.md b/NEWS.md
index 3d431ca783..16151dd6e1 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -25,6 +25,7 @@ The following bundled gem is added.
 
 The following bundled gems are updated.
 
+* net-imap 0.5.5
 * rbs 3.8.1
 * bigdecimal 3.1.9
 
diff --git a/gems/bundled_gems b/gems/bundled_gems
index 079071fe10..4dd4160221 100644
--- a/gems/bundled_gems
+++ b/gems/bundled_gems
@@ -13,7 +13,7 @@ test-unit           3.6.7   https://github.com/test-unit/test-unit
 rexml               3.4.0   https://github.com/ruby/rexml
 rss                 0.3.1   https://github.com/ruby/rss
 net-ftp             0.3.8   https://github.com/ruby/net-ftp
-net-imap            0.5.4   https://github.com/ruby/net-imap
+net-imap            0.5.5   https://github.com/ruby/net-imap
 net-pop             0.1.2   https://github.com/ruby/net-pop
 net-smtp            0.5.0   https://github.com/ruby/net-smtp
 matrix              0.4.2   https://github.com/ruby/matrix