diff --git a/Gemfile b/Gemfile
index 7b6ae23199..0309937165 100644
--- a/Gemfile
+++ b/Gemfile
@@ -31,7 +31,7 @@ gem 'redis'
 gem 'rubyzip', '>= 1.3.0'
 gem 'sequel', '~> 5.99'
 gem 'sequel_pg', require: 'sequel'
-gem 'sinatra', '~> 3.2'
+gem 'sinatra', '~> 4.2'
 gem 'sinatra-contrib'
 gem 'statsd-ruby', '~> 1.5.0'
 gem 'steno'
diff --git a/Gemfile.lock b/Gemfile.lock
index dc6132d9b5..731c703ee5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -316,7 +316,7 @@ GEM
     multipart-parser (0.1.1)
     multipart-post (2.4.1)
     mustache (1.1.1)
-    mustermann (3.0.0)
+    mustermann (3.0.4)
       ruby2_keywords (~> 0.0.1)
     mutex_m (0.3.0)
     mysql2 (0.5.7)
@@ -369,17 +369,18 @@ GEM
     puma (7.1.0)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (2.2.21)
-    rack-protection (3.2.0)
+    rack (3.2.4)
+    rack-protection (4.2.1)
       base64 (>= 0.1.0)
-      rack (~> 2.2, >= 2.2.4)
-    rack-session (1.0.2)
-      rack (< 3)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.1.1)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0)
     rack-test (2.2.0)
       rack (>= 1.3)
-    rackup (1.0.1)
-      rack (< 3)
-      webrick
+    rackup (2.3.1)
+      rack (>= 3)
     rails-dom-testing (2.3.0)
       activesupport (>= 5.0.0)
       minitest
@@ -521,16 +522,18 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    sinatra (3.2.0)
+    sinatra (4.2.1)
+      logger (>= 1.6.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.2.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.2.1)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    sinatra-contrib (3.2.0)
+    sinatra-contrib (4.2.1)
       multi_json (>= 0.0.2)
       mustermann (~> 3.0)
-      rack-protection (= 3.2.0)
-      sinatra (= 3.2.0)
+      rack-protection (= 4.2.1)
+      sinatra (= 4.2.1)
       tilt (~> 2.0)
     solargraph (0.57.0)
       backport (~> 1.2)
@@ -586,7 +589,6 @@ GEM
       addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
-    webrick (1.9.1)
     xml-simple (1.1.9)
       rexml
     yajl-ruby (1.4.3)
@@ -673,7 +675,7 @@ DEPENDENCIES
   rubyzip (>= 1.3.0)
   sequel (~> 5.99)
   sequel_pg
-  sinatra (~> 3.2)
+  sinatra (~> 4.2)
   sinatra-contrib
   solargraph
   spork!