diff --git a/Gemfile b/Gemfile
index cdf3c0e10..8c94f5af4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'eventmachine', '~> 1.2', '>= 1.2.7'
 gem 'thin', '~> 2.0'
 gem 'sinatra', '~> 4.1'
 gem 'rack', '~> 3.2'
-gem 'rack-protection', '~> 4.1.1'
+gem 'rack-protection', '~> 4.2.1'
 gem 'em-websocket', '~> 0.5.3' # WebSocket support
 gem 'uglifier', '~> 4.2'
 gem 'mime-types', '~> 3.7'
diff --git a/Gemfile.lock b/Gemfile.lock
index 2b118a34d..d21a2800d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -155,7 +155,7 @@ GEM
       rqrcode_core (~> 1.0)
     racc (1.8.1)
     rack (3.2.3)
-    rack-protection (4.1.1)
+    rack-protection (4.2.1)
       base64 (>= 0.1.0)
       logger (>= 1.6.0)
       rack (>= 3.0.0, < 4)
@@ -221,11 +221,11 @@ GEM
       rexml (~> 3.2, >= 3.2.5)
       rubyzip (>= 1.2.2, < 4.0)
       websocket (~> 1.0)
-    sinatra (4.1.1)
+    sinatra (4.2.1)
       logger (>= 1.6.0)
       mustermann (~> 3.0)
       rack (>= 3.0.0, < 4)
-      rack-protection (= 4.1.1)
+      rack-protection (= 4.2.1)
       rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
     slack-notifier (2.4.0)
@@ -322,7 +322,7 @@ DEPENDENCIES
   pry-byebug (~> 3.11)
   qr4r (~> 0.6.1)
   rack (~> 3.2)
-  rack-protection (~> 4.1.1)
+  rack-protection (~> 4.2.1)
   rake (~> 13.3)
   rdoc (~> 6.15)
   rest-client (~> 2.1.0)