diff --git a/Calculator-LTI/Gemfile b/Calculator-LTI/Gemfile
index aa84986..e86f328 100644
--- a/Calculator-LTI/Gemfile
+++ b/Calculator-LTI/Gemfile
@@ -30,7 +30,7 @@ gem 'jbuilder', '~> 2.5'
 # Use ActiveModel has_secure_password
 # gem 'bcrypt', '~> 3.1.7'
 # Nokogiri is an open source software library to parse HTML and XML in Ruby. Explicitly updated to counter security vulnerability.
-gem 'nokogiri', '~> 1.10.4'
+gem 'nokogiri', '~> 1.13.2'
 
 # Use Capistrano for deployment
 # gem 'capistrano-rails', group: :development
diff --git a/Calculator-LTI/Gemfile.lock b/Calculator-LTI/Gemfile.lock
index 48cf2e7..725ca17 100644
--- a/Calculator-LTI/Gemfile.lock
+++ b/Calculator-LTI/Gemfile.lock
@@ -90,16 +90,18 @@ GEM
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
     mini_mime (0.1.4)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.0)
     minitest (5.10.3)
     multi_json (1.12.2)
     nio4r (2.1.0)
-    nokogiri (1.10.4)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.13.2)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     oauth (0.5.3)
     public_suffix (3.0.0)
     puma (4.3.1)
       nio4r (~> 2.0)
+    racc (1.6.0)
     rack (2.0.8)
     rack-test (0.7.0)
       rack (>= 1.0, < 3)
@@ -194,7 +196,7 @@ DEPENDENCIES
   ims-lti (~> 1.1.8)
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  nokogiri (~> 1.10.4)
+  nokogiri (~> 1.13.2)
   puma (~> 4.3)
   rails (~> 5.1.4)
   sass-rails (~> 5.0)