diff --git a/package.json b/package.json
index 4a82de56e1..3ebbdb7323 100644
--- a/package.json
+++ b/package.json
@@ -60,7 +60,7 @@
     "clean-webpack-plugin": "^3.0.0",
     "copy-webpack-plugin": "^6.0.3",
     "css-loader": "^3.6.0",
-    "cssnano": "^4.1.10",
+    "cssnano": "^5.0.0",
     "depcheck": "^1.0.0",
     "dojo-util": "1.16.3",
     "dojo-webpack-loader": "^0.9.2",
@@ -97,7 +97,7 @@
     "markdownlint": "^0.20.4",
     "markdownlint-cli": "^0.23.2",
     "npm-run-all": "^4.1.5",
-    "optimize-css-assets-webpack-plugin": "^5.0.3",
+    "optimize-css-assets-webpack-plugin": "^6.0.0",
     "prettier": "^2.0.5",
     "prettier-plugin-html-template-literals": "^1.0.5",
     "style-loader": "^1.2.1",