diff --git a/Gemfile b/Gemfile
index e1a27f3ed..4acc1a70d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -33,7 +33,7 @@ gem "simple_captcha2", "0.4.0", require: "simple_captcha"
 # Background processing
 
 gem "sidekiq", "3.4.2"
-gem "sinatra", "1.4.6"
+gem "sinatra", "1.4.7"
 
 # Scheduled processing
 
diff --git a/Gemfile.lock b/Gemfile.lock
index a90ec7472..13089c56c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -694,8 +694,8 @@ GEM
       json (~> 1.8)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.0)
-    sinatra (1.4.6)
-      rack (~> 1.4)
+    sinatra (1.4.7)
+      rack (~> 1.5)
       rack-protection (~> 1.4)
       tilt (>= 1.3, < 3)
     sinon-rails (1.15.0)
@@ -885,7 +885,7 @@ DEPENDENCIES
   sidetiq (= 0.6.3)
   simple_captcha2 (= 0.4.0)
   simplecov (= 0.11.1)
-  sinatra (= 1.4.6)
+  sinatra (= 1.4.7)
   sinon-rails (= 1.15.0)
   spring (= 1.6.1)
   spring-commands-cucumber (= 1.0.1)