diff --git a/packages/optimizer/demo/markdown/package-lock.json b/packages/optimizer/demo/markdown/package-lock.json
index 75dcff032..f1a742126 100644
--- a/packages/optimizer/demo/markdown/package-lock.json
+++ b/packages/optimizer/demo/markdown/package-lock.json
@@ -129,9 +129,9 @@
       }
     },
     "entities": {
-      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/entities/-/entities-2.0.0.tgz",
-      "integrity": "sha512-D9f7V0JSRwIxlRI2mjMqufDrRDnx8p+eEOz7aUM9SuvF8gsBzra0/6tbjl1m8eQHrZlYj6PxqE00hZ1SAIKPLw==",
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/entities/-/entities-2.0.2.tgz",
+      "integrity": "sha512-dmD3AvJQBUjKpcNkoqr+x+IF0SdRtPz9Vk0uTy4yWqga9ibB6s4v++QFWNohjiUGoMlF552ZvNyXDxz5iW0qmw==",
       "dev": true
     },
     "extend": {
@@ -266,23 +266,23 @@
       }
     },
     "linkify-it": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/linkify-it/-/linkify-it-2.2.0.tgz",
-      "integrity": "sha512-GnAl/knGn+i1U/wjBz3akz2stz+HrHLsxMwHQGofCDfPvlf+gDKN58UtfmUquTY4/MXeE2x7k19KQmeoZi94Iw==",
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/linkify-it/-/linkify-it-3.0.1.tgz",
+      "integrity": "sha512-/CEnQ8L2N1vUK+sL2W/ZpTsYKEhOG0MlS9h07Q5GF3kfyVF85ItCRdU38rI89CJtmWMESt0xKaCd58vB0fzWeQ==",
       "dev": true,
       "requires": {
         "uc.micro": "^1.0.1"
       }
     },
     "markdown-it": {
-      "version": "10.0.0",
-      "resolved": "https://registry.npmjs.org/markdown-it/-/markdown-it-10.0.0.tgz",
-      "integrity": "sha512-YWOP1j7UbDNz+TumYP1kpwnP0aEa711cJjrAQrzd0UXlbJfc5aAq0F/PZHjiioqDC1NKgvIMX+o+9Bk7yuM2dg==",
+      "version": "11.0.0",
+      "resolved": "https://registry.npmjs.org/markdown-it/-/markdown-it-11.0.0.tgz",
+      "integrity": "sha512-+CvOnmbSubmQFSA9dKz1BRiaSMV7rhexl3sngKqFyXSagoA3fBdJQ8oZWtRy2knXdpDXaBw44euz37DeJQ9asg==",
       "dev": true,
       "requires": {
         "argparse": "^1.0.7",
         "entities": "~2.0.0",
-        "linkify-it": "^2.0.0",
+        "linkify-it": "^3.0.1",
         "mdurl": "^1.0.1",
         "uc.micro": "^1.0.5"
       }
diff --git a/packages/optimizer/demo/markdown/package.json b/packages/optimizer/demo/markdown/package.json
index c73995125..340580c67 100644
--- a/packages/optimizer/demo/markdown/package.json
+++ b/packages/optimizer/demo/markdown/package.json
@@ -4,7 +4,7 @@
   "version": "1.0.0",
   "description": "AMP Optimizer supports converting Markdown to AMPHTML.",
   "devDependencies": {
-    "markdown-it": "10.0.0",
+    "markdown-it": "11.0.0",
     "probe-image-size": "5.0.0"
   }
 }