diff --git a/Gemfile b/Gemfile
index 29d1d7745aee2c16fc848ae0d6fd8217a205a28f..3bce5127dc43bfd12b584c1af98d06528af000e1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -33,7 +33,7 @@ gem "simple_captcha2", "0.3.4", require: "simple_captcha"
 # Background processing
 
 gem "sidekiq", "3.3.3"
-gem "sinatra", "1.4.5"
+gem "sinatra", "1.4.6"
 
 # Scheduled processing
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 29730f859141962a6973f76f4ab4226e5305c511..a5a5985bc4e7c19782ba06e52b9aaba84d653a6b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -632,10 +632,10 @@ GEM
     simple_captcha2 (0.3.4)
       rails (>= 4.1)
     simple_oauth (0.2.0)
-    sinatra (1.4.5)
+    sinatra (1.4.6)
       rack (~> 1.4)
       rack-protection (~> 1.4)
-      tilt (~> 1.3, >= 1.3.4)
+      tilt (>= 1.3, < 3)
     sinon-rails (1.10.3)
       railties (>= 3.1)
     slop (3.6.0)
@@ -805,7 +805,7 @@ DEPENDENCIES
   sidekiq (= 3.3.3)
   sidetiq (= 0.6.3)
   simple_captcha2 (= 0.3.4)
-  sinatra (= 1.4.5)
+  sinatra (= 1.4.6)
   sinon-rails (= 1.10.3)
   spring (= 1.3.3)
   spring-commands-cucumber (= 1.0.1)