diff --git a/Gemfile b/Gemfile
index a357b4987..032605681 100644
--- a/Gemfile
+++ b/Gemfile
@@ -27,7 +27,7 @@ gem 'iri', '0.8.0'
 gem 'loog', '0.5.1'
 gem 'minitest', '5.22.2', require: false
 gem 'pgtk', '0.9.2'
-gem 'rack', '3.0.9'
+gem 'rack', '3.0.9.1'
 gem 'rack-ssl', '1.4.1'
 gem 'rack-test', '2.1.0'
 gem 'rake', '13.1.0', require: false
diff --git a/Gemfile.lock b/Gemfile.lock
index 0a0e8b81b..4e24729ec 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -126,7 +126,7 @@ GEM
     psych (5.1.2)
       stringio
     racc (1.7.3)
-    rack (3.0.9)
+    rack (3.0.9.1)
     rack-protection (4.0.0)
       base64 (>= 0.1.0)
       rack (>= 3.0.0, < 4)
@@ -281,7 +281,7 @@ DEPENDENCIES
   loog (= 0.5.1)
   minitest (= 5.22.2)
   pgtk (= 0.9.2)
-  rack (= 3.0.9)
+  rack (= 3.0.9.1)
   rack-ssl (= 1.4.1)
   rack-test (= 2.1.0)
   rake (= 13.1.0)