diff --git a/Gemfile b/Gemfile
index 2528587f..2ce9eec6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -41,7 +41,7 @@ gem "bower-rails", "~> 0.11.0"
 gem "responders", "~> 2.4.0"
 gem 'nokogiri', '1.10.8'
 
-gem 'uglifier', '~> 3.2.0'
+gem 'uglifier', '~> 4.2.0'
 gem 'rspec-mocks', '3.6.0'
 
 gem 'honeycomb-beeline'
diff --git a/Gemfile.lock b/Gemfile.lock
index db0d34ed..3d6fa809 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -151,7 +151,7 @@ GEM
     equivalent-xml (0.6.0)
       nokogiri (>= 1.4.3)
     erubis (2.7.0)
-    execjs (2.6.0)
+    execjs (2.7.0)
     faraday (0.12.1)
       multipart-post (>= 1.2, < 3)
     fastercsv (1.5.5)
@@ -432,7 +432,7 @@ GEM
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
     uber (0.0.15)
-    uglifier (3.2.0)
+    uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
     unf (0.1.4)
       unf_ext
@@ -511,7 +511,7 @@ DEPENDENCIES
   solrizer-fedora!
   sprockets (~> 2.12.4)
   timecop
-  uglifier (~> 3.2.0)
+  uglifier (~> 4.2.0)
   unicorn (~> 5.3.0)
   whenever