diff --git a/package.json b/package.json
index 83f6f1c..ac81b64 100644
--- a/package.json
+++ b/package.json
@@ -10,7 +10,7 @@
     "rehype-stringify": "^6.0.1",
     "remark-parse": "^7.0.2",
     "remark-rehype": "^5.0.0",
-    "unified": "^8.4.2"
+    "unified": "^9.0.0"
   },
   "devDependencies": {
     "@types/node": "^13.7.6",
diff --git a/yarn.lock b/yarn.lock
index e63a5b7..a7e3fe9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7133,13 +7133,14 @@ unicode-property-aliases-ecmascript@^1.0.4:
   resolved "https://registry.yarnpkg.com/unicode-property-aliases-ecmascript/-/unicode-property-aliases-ecmascript-1.0.5.tgz#a9cc6cc7ce63a0a3023fc99e341b94431d405a57"
   integrity sha512-L5RAqCfXqAwR3RriF8pM0lU0w4Ryf/GgzONwi6KnL1taJQa7x1TCxdJnILX59WIGOwR57IVxn7Nej0fz1Ny6fw==
 
-unified@^8.4.2:
-  version "8.4.2"
-  resolved "https://registry.yarnpkg.com/unified/-/unified-8.4.2.tgz#13ad58b4a437faa2751a4a4c6a16f680c500fff1"
-  integrity sha512-JCrmN13jI4+h9UAyKEoGcDZV+i1E7BLFuG7OsaDvTXI5P0qhHX+vZO/kOhz9jn8HGENDKbwSeB0nVOg4gVStGA==
+unified@^9.0.0:
+  version "9.0.0"
+  resolved "https://registry.yarnpkg.com/unified/-/unified-9.0.0.tgz#12b099f97ee8b36792dbad13d278ee2f696eed1d"
+  integrity sha512-ssFo33gljU3PdlWLjNp15Inqb77d6JnJSfyplGJPT/a+fNRNyCBeveBAYJdO5khKdF6WVHa/yYCC7Xl6BDwZUQ==
   dependencies:
     bail "^1.0.0"
     extend "^3.0.0"
+    is-buffer "^2.0.0"
     is-plain-obj "^2.0.0"
     trough "^1.0.0"
     vfile "^4.0.0"