diff --git a/site/package.json b/site/package.json
index 7f16966..a28c76c 100644
--- a/site/package.json
+++ b/site/package.json
@@ -26,7 +26,7 @@
     "gatsby-transformer-remark": "^2.6.21",
     "gatsby-transformer-sharp": "2.2.13",
     "katex": "0.11.0",
-    "prismjs": "1.17.1",
+    "prismjs": "1.21.0",
     "react": "16.9.0",
     "react-dom": "16.9.0",
     "react-helmet": "5.2.1",
diff --git a/site/yarn.lock b/site/yarn.lock
index 99bbf92..2ed0aab 100644
--- a/site/yarn.lock
+++ b/site/yarn.lock
@@ -10943,10 +10943,10 @@ pretty-error@^2.1.1:
     renderkid "^2.0.1"
     utila "~0.4"
 
-prismjs@1.17.1:
-  version "1.17.1"
-  resolved "https://registry.npmjs.org/prismjs/-/prismjs-1.17.1.tgz#e669fcbd4cdd873c35102881c33b14d0d68519be"
-  integrity sha512-PrEDJAFdUGbOP6xK/UsfkC5ghJsPJviKgnQOoxaDbBjwc8op68Quupwt1DeAFoG8GImPhiKXAvvsH7wDSLsu1Q==
+prismjs@1.21.0:
+  version "1.21.0"
+  resolved "https://registry.yarnpkg.com/prismjs/-/prismjs-1.21.0.tgz#36c086ec36b45319ec4218ee164c110f9fc015a3"
+  integrity sha512-uGdSIu1nk3kej2iZsLyDoJ7e9bnPzIgY0naW/HdknGj61zScaprVEVGHrPoXqI+M9sP0NDnTK2jpkvmldpuqDw==
   optionalDependencies:
     clipboard "^2.0.0"