diff --git a/Gemfile b/Gemfile
index d59f2f7..e640713 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 3.12'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 6c4aa0f..ecec582 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -355,7 +355,7 @@ GEM
       cairo-gobject (= 3.3.7)
       gio2 (= 3.3.7)
     public_suffix (3.1.1)
-    puma (3.12.1)
+    puma (3.12.4)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -564,7 +564,7 @@ DEPENDENCIES
   pdf-reader
   pdftoimage
   poppler
-  puma (~> 3.11)
+  puma (~> 3.12)
   rails (~> 5.2.1)
   rest-client
   riiif