diff --git a/Gemfile b/Gemfile
index 5c9605ec..c97b485a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ ruby '2.7.6'
 
 gem 'activesupport'
 gem "erector", "~> 0.10.0"
-gem "sinatra", "~> 3.0.3"
+gem "sinatra", "~> 3.0.4"
 gem "sinatra-contrib", "~> 3.0.3"
 gem "nokogiri"
 gem "thin", "1.8.1"
diff --git a/Gemfile.lock b/Gemfile.lock
index ae4b1e12..3c530177 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -56,7 +56,7 @@ GEM
     rack-codehighlighter (0.6.0)
       nokogiri (>= 1.4.1)
       rack (>= 2.0.0)
-    rack-protection (3.0.3)
+    rack-protection (3.0.4)
       rack
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -86,16 +86,16 @@ GEM
     sass (3.4.23)
     sassc (2.4.0)
       ffi (~> 1.9)
-    sinatra (3.0.3)
+    sinatra (3.0.4)
       mustermann (~> 3.0)
       rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.0.3)
+      rack-protection (= 3.0.4)
       tilt (~> 2.0)
-    sinatra-contrib (3.0.3)
+    sinatra-contrib (3.0.4)
       multi_json
       mustermann (~> 3.0)
-      rack-protection (= 3.0.3)
-      sinatra (= 3.0.3)
+      rack-protection (= 3.0.4)
+      sinatra (= 3.0.4)
       tilt (~> 2.0)
     sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
@@ -137,7 +137,7 @@ DEPENDENCIES
   rspec
   rubyzip
   sass
-  sinatra (~> 3.0.3)
+  sinatra (~> 3.0.4)
   sinatra-contrib (~> 3.0.3)
   sprockets
   thin (= 1.8.1)