diff --git a/node_modules/y18n/CHANGELOG.md b/node_modules/y18n/CHANGELOG.md
index c259076ad6da2..a3d5bcd534916 100644
--- a/node_modules/y18n/CHANGELOG.md
+++ b/node_modules/y18n/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
 
+
+### 4.0.1 (2020-11-30)
+
+### Bug Fixes
+
+* address prototype pollution issue ([#108](https://www.github.com/yargs/y18n/issues/108)) ([a9ac604](https://www.github.com/yargs/y18n/commit/a9ac604abf756dec9687be3843e2c93bfe581f25))
+
 <a name="4.0.0"></a>
 # [4.0.0](https://github.com/yargs/y18n/compare/v3.2.1...v4.0.0) (2017-10-10)
 
diff --git a/node_modules/y18n/index.js b/node_modules/y18n/index.js
index d72068162876a..727362aac0664 100644
--- a/node_modules/y18n/index.js
+++ b/node_modules/y18n/index.js
@@ -11,7 +11,7 @@ function Y18N (opts) {
   this.fallbackToLanguage = typeof opts.fallbackToLanguage === 'boolean' ? opts.fallbackToLanguage : true
 
   // internal stuff.
-  this.cache = {}
+  this.cache = Object.create(null)
   this.writeQueue = []
 }
 
diff --git a/node_modules/y18n/package.json b/node_modules/y18n/package.json
index 24016e224a737..a8bab2cc194f8 100644
--- a/node_modules/y18n/package.json
+++ b/node_modules/y18n/package.json
@@ -1,30 +1,32 @@
 {
-  "_from": "y18n@^4.0.0",
-  "_id": "y18n@4.0.0",
+  "_from": "y18n@4.0.1",
+  "_id": "y18n@4.0.1",
   "_inBundle": false,
-  "_integrity": "sha512-r9S/ZyXu/Xu9q1tYlpsLIsa3EeLXXk0VwlxqTcFRfg9EhMW+17kbt9G0NrgCmhGb5vT2hyhJZLfDGx+7+5Uj/w==",
+  "_integrity": "sha512-wNcy4NvjMYL8gogWWYAO7ZFWFfHcbdbE57tZO8e4cbpj8tfUcwrwqSl3ad8HxpYWCdXcJUCeKKZS62Av1affwQ==",
   "_location": "/y18n",
   "_phantomChildren": {},
   "_requested": {
-    "type": "range",
+    "type": "version",
     "registry": true,
-    "raw": "y18n@^4.0.0",
+    "raw": "y18n@4.0.1",
     "name": "y18n",
     "escapedName": "y18n",
-    "rawSpec": "^4.0.0",
+    "rawSpec": "4.0.1",
     "saveSpec": null,
-    "fetchSpec": "^4.0.0"
+    "fetchSpec": "4.0.1"
   },
   "_requiredBy": [
+    "#USER",
+    "/",
     "/cacache",
     "/libnpx",
-    "/npm-profile/cacache",
-    "/npm-registry-fetch/cacache"
+    "/nyc/yargs",
+    "/yargs"
   ],
-  "_resolved": "https://registry.npmjs.org/y18n/-/y18n-4.0.0.tgz",
-  "_shasum": "95ef94f85ecc81d007c264e190a120f0a3c8566b",
-  "_spec": "y18n@^4.0.0",
-  "_where": "/Users/rebecca/code/npm/node_modules/cacache",
+  "_resolved": "https://registry.npmjs.org/y18n/-/y18n-4.0.1.tgz",
+  "_shasum": "8db2b83c31c5d75099bb890b23f3094891e247d4",
+  "_spec": "y18n@4.0.1",
+  "_where": "/Users/ruyadorno/Documents/workspace/cli-release/cli",
   "author": {
     "name": "Ben Coe",
     "email": "ben@npmjs.com"
@@ -66,5 +68,5 @@
     "release": "standard-version",
     "test": "nyc mocha"
   },
-  "version": "4.0.0"
+  "version": "4.0.1"
 }
diff --git a/package-lock.json b/package-lock.json
index dcb81c9349668..7a7815dd944f6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6156,9 +6156,9 @@
       "integrity": "sha1-pcbVMr5lbiPbgg77lDofBJmNY68="
     },
     "y18n": {
-      "version": "4.0.0",
-      "resolved": "https://registry.npmjs.org/y18n/-/y18n-4.0.0.tgz",
-      "integrity": "sha512-r9S/ZyXu/Xu9q1tYlpsLIsa3EeLXXk0VwlxqTcFRfg9EhMW+17kbt9G0NrgCmhGb5vT2hyhJZLfDGx+7+5Uj/w=="
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/y18n/-/y18n-4.0.1.tgz",
+      "integrity": "sha512-wNcy4NvjMYL8gogWWYAO7ZFWFfHcbdbE57tZO8e4cbpj8tfUcwrwqSl3ad8HxpYWCdXcJUCeKKZS62Av1affwQ=="
     },
     "yallist": {
       "version": "3.0.3",