diff --git a/Gemfile b/Gemfile
index fa60a41e..daae633e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -81,3 +81,7 @@ group :development, :test do
   gem 'rubocop', '~> 0.51.0', require: false
   gem 'test-unit', '~> 3.0'
 end
+
+# Security upgrades
+gem 'actionview', '>= 5.1.6.2'
+gem "nokogiri", ">= 1.10.4"
diff --git a/app/views/authorizations/_authorization.html.erb b/app/views/authorizations/_authorization.html.erb
index 915c54b9..437d5831 100644
--- a/app/views/authorizations/_authorization.html.erb
+++ b/app/views/authorizations/_authorization.html.erb
@@ -11,14 +11,14 @@
       <div class="media-body">
         <p><%= link_to authorization.url, authorization.url %></p>
         <p>
-          <%= link_to signin_path(provider), class: ['btn', 'btn-social', "btn-#{provider}"] do %>
+          <%= link_to signin_path(provider), method: :post, class: ['btn', 'btn-social', "btn-#{provider}"] do %>
             <span class="fa fa-<%= provider %>"></span> <%= t("reconnect_with.#{provider}") %>
           <% end %>
         </p>
       </div>
     </div>
   <% else %>
-    <%= link_to signin_path(provider), class: ['btn', 'btn-social', "btn-#{provider}"] do %>
+    <%= link_to signin_path(provider), method: :post, class: ['btn', 'btn-social', "btn-#{provider}"] do %>
       <span class="fa fa-<%= provider %>"></span> <%= t("connect_with.#{provider}") %>
     <% end %>
   <% end %>
diff --git a/app/views/shared/_header.html.erb b/app/views/shared/_header.html.erb
index 469a4f5b..ad4a4c46 100644
--- a/app/views/shared/_header.html.erb
+++ b/app/views/shared/_header.html.erb
@@ -16,13 +16,13 @@
           <li><%= link_to t('sign_out'), signout_path, method: :delete %></li>
         <% else %>
           <li>
-            <%= link_to signin_path(Authorization::PROVIDER_GITHUB) do %>
+            <%= link_to signin_path(Authorization::PROVIDER_GITHUB), method: :post do %>
               <%= image_tag('github.png', width: 24) %>
               <%= t('signin_with.github') %>
             <% end %>
           </li>
           <li>
-            <%= link_to signin_path(Authorization::PROVIDER_TWITTER) do %>
+            <%= link_to signin_path(Authorization::PROVIDER_TWITTER), method: :post do %>
               <%= image_tag('twitter.png', width: 24) %>
               <%= t('signin_with.twitter') %>
             <% end %>
diff --git a/app/views/welcome/_tomatoes_timer.html.erb b/app/views/welcome/_tomatoes_timer.html.erb
index 07b981bc..a7c17f3a 100644
--- a/app/views/welcome/_tomatoes_timer.html.erb
+++ b/app/views/welcome/_tomatoes_timer.html.erb
@@ -47,11 +47,11 @@
     <div id="tomato_signin">
       <p><%= t('timer.signin_to_start_tracking') %></p>
 
-      <%= link_to signin_path(Authorization::PROVIDER_GITHUB), class: 'btn btn-block btn-social btn-github' do %>
+      <%= link_to signin_path(Authorization::PROVIDER_GITHUB), method: :post, class: 'btn btn-block btn-social btn-github' do %>
         <span class="fa fa-github"></span> <%= t('signin_with.github') %>
       <% end %>
 
-      <%= link_to signin_path(Authorization::PROVIDER_TWITTER), class: 'btn btn-block btn-social btn-twitter' do %>
+      <%= link_to signin_path(Authorization::PROVIDER_TWITTER), method: :post, class: 'btn btn-block btn-social btn-twitter' do %>
         <span class="fa fa-twitter"></span> <%= t('signin_with.twitter') %>
       <% end %>
 
diff --git a/app/views/welcome/index.html.erb b/app/views/welcome/index.html.erb
index d47f5a26..da74132d 100644
--- a/app/views/welcome/index.html.erb
+++ b/app/views/welcome/index.html.erb
@@ -17,11 +17,11 @@
   <% else %>
     <div class="intro">
       <p>
-        <%= link_to signin_path(Authorization::PROVIDER_GITHUB), class: 'btn btn-lg btn-social btn-github' do %>
+        <%= link_to signin_path(Authorization::PROVIDER_GITHUB), method: :post, class: 'btn btn-lg btn-social btn-github' do %>
           <span class="fa fa-github"></span> <%= t('signin_with.github') %>
         <% end %>
 
-        <%= link_to signin_path(Authorization::PROVIDER_TWITTER), class: 'btn btn-lg btn-social btn-twitter' do %>
+        <%= link_to signin_path(Authorization::PROVIDER_TWITTER), method: :post, class: 'btn btn-lg btn-social btn-twitter' do %>
           <span class="fa fa-twitter"></span> <%= t('signin_with.twitter') %>
         <% end %>
       </p>