diff --git a/Gemfile b/Gemfile
index 57c2b48..83f142b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,7 @@
 source "https://rubygems.org"
 
 # synk
-gem "nokogiri", "~> 1.8.1"
+gem "nokogiri", "~> 1.13.4"
 gem "rack-protection", "~> 2.0.0"
 
 # jekyll
diff --git a/Gemfile.lock b/Gemfile.lock
index b3b0c61..14f39e5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -59,16 +59,18 @@ GEM
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
     mercenary (0.3.6)
-    mini_portile2 (2.3.0)
+    mini_portile2 (2.8.0)
     minitest (5.10.3)
     multipart-post (2.0.0)
-    nokogiri (1.8.1)
-      mini_portile2 (~> 2.3.0)
+    nokogiri (1.13.4)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     octokit (4.7.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     pathutil (0.16.0)
       forwardable-extended (~> 2.6)
     public_suffix (3.0.0)
+    racc (1.6.0)
     rack (2.0.3)
     rack-protection (2.0.0)
       rack
@@ -102,7 +104,7 @@ DEPENDENCIES
   jekyll-seo-tag
   jekyll-sitemap
   liquid_reading_time
-  nokogiri (~> 1.8.1)
+  nokogiri (~> 1.13.4)
   rack-protection (~> 2.0.0)
 
 BUNDLED WITH