diff --git a/Gemfile b/Gemfile
index 5679b5672..7ae664cc7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -36,7 +36,7 @@ gem "simple_captcha2", "0.4.3", require: "simple_captcha"
 # Background processing
 
 gem "redis", "3.3.5" # Pinned to 3.3.x because of https://github.com/antirez/redis/issues/4272
-gem "sidekiq", "5.1.3"
+gem "sidekiq", "5.2.3"
 
 # Scheduled processing
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 90e19ad4c..782614e52 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -125,7 +125,7 @@ GEM
       sprockets (< 4.0)
     concurrent-ruby (1.1.3)
     configurate (0.3.1)
-    connection_pool (2.2.1)
+    connection_pool (2.2.2)
     coveralls (0.8.22)
       json (>= 1.8, < 3)
       simplecov (~> 0.16.1)
@@ -488,7 +488,7 @@ GEM
       json-jwt (>= 1.9.0)
       rack
     rack-piwik (0.3.0)
-    rack-protection (2.0.1)
+    rack-protection (2.0.4)
       rack
     rack-rewrite (1.5.1)
     rack-ssl (1.4.1)
@@ -644,9 +644,8 @@ GEM
     shellany (0.0.1)
     shoulda-matchers (3.1.2)
       activesupport (>= 4.0.0)
-    sidekiq (5.1.3)
-      concurrent-ruby (~> 1.0)
-      connection_pool (~> 2.2, >= 2.2.0)
+    sidekiq (5.2.3)
+      connection_pool (~> 2.2, >= 2.2.2)
       rack-protection (>= 1.5.0)
       redis (>= 3.3.5, < 5)
     sidekiq-cron (0.6.3)
@@ -879,7 +878,7 @@ DEPENDENCIES
   sass-rails (= 5.0.7)
   secure_headers (= 5.0.5)
   shoulda-matchers (= 3.1.2)
-  sidekiq (= 5.1.3)
+  sidekiq (= 5.2.3)
   sidekiq-cron (= 0.6.3)
   simple_captcha2 (= 0.4.3)
   simplecov (= 0.16.1)