diff --git a/html/package.json b/html/package.json
index 5f44a5d..c1a26eb 100644
--- a/html/package.json
+++ b/html/package.json
@@ -55,7 +55,7 @@
     "ts-loader": "^8.0.17",
     "tslint": "^6.1.3",
     "tslint-loader": "^3.5.4",
-    "typescript": "^3.9.7",
+    "typescript": "^3.9.9",
     "webpack": "4.46.0",
     "webpack-cli": "^4.5.0",
     "webpack-dev-server": "^3.11.2",
diff --git a/html/yarn.lock b/html/yarn.lock
index 2ff00de..800f6ff 100644
--- a/html/yarn.lock
+++ b/html/yarn.lock
@@ -8090,10 +8090,10 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-typescript@^3.9.7:
-  version "3.9.7"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.7.tgz#98d600a5ebdc38f40cb277522f12dc800e9e25fa"
-  integrity sha512-BLbiRkiBzAwsjut4x/dsibSTB6yWpwT5qWmC2OfuCg3GgVQCSgMs4vEctYPhsaGtd0AeuuHMkjZ2h2WG8MSzRw==
+typescript@^3.9.9:
+  version "3.9.9"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.9.tgz#e69905c54bc0681d0518bd4d587cc6f2d0b1a674"
+  integrity sha512-kdMjTiekY+z/ubJCATUPlRDl39vXYiMV9iyeMuEuXZh2we6zz80uovNN2WlAxmmdE/Z/YQe+EbOEXB5RHEED3w==
 
 unc-path-regex@^0.1.2:
   version "0.1.2"