diff --git a/rails/implicit_render/Gemfile b/rails/implicit_render/Gemfile
index 881dc69..81dcee4 100644
--- a/rails/implicit_render/Gemfile
+++ b/rails/implicit_render/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '5.2.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~>1.3.6'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 3.12'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/rails/implicit_render/Gemfile.lock b/rails/implicit_render/Gemfile.lock
index dd2d8b6..a36eb98 100644
--- a/rails/implicit_render/Gemfile.lock
+++ b/rails/implicit_render/Gemfile.lock
@@ -97,7 +97,7 @@ GEM
     nokogiri (1.10.1)
       mini_portile2 (~> 2.4.0)
     public_suffix (3.0.3)
-    puma (3.12.1)
+    puma (3.12.6)
     rack (2.0.6)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -188,7 +188,7 @@ DEPENDENCIES
   coffee-rails (~> 4.2)
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.7)
+  puma (~> 3.12)
   rails (= 5.2.1)
   sass-rails (~> 5.0)
   selenium-webdriver