diff --git a/Chapter04/server-smtp/package-lock.json b/Chapter04/server-smtp/package-lock.json
index 3333bf0..716976e 100644
--- a/Chapter04/server-smtp/package-lock.json
+++ b/Chapter04/server-smtp/package-lock.json
@@ -9,7 +9,7 @@
       "version": "1.0.0",
       "license": "ISC",
       "dependencies": {
-        "smtp-server": "^3.13.0"
+        "smtp-server": "^3.13.2"
       }
     },
     "node_modules/base32.js": {
@@ -26,21 +26,30 @@
       "integrity": "sha512-Bm6H79i01DjgGTCWjUuCjJ6QDo1HB96PT/xCYuyJUP9WFbVDrLSbG4EZCvOCun2rNswZb0c3e4Jt/ws795esHA=="
     },
     "node_modules/nodemailer": {
-      "version": "6.9.4",
-      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-6.9.4.tgz",
-      "integrity": "sha512-CXjQvrQZV4+6X5wP6ZIgdehJamI63MFoYFGGPtHudWym9qaEHDNdPzaj5bfMCvxG1vhAileSWW90q7nL0N36mA==",
+      "version": "6.9.9",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-6.9.9.tgz",
+      "integrity": "sha512-dexTll8zqQoVJEZPwQAKzxxtFn0qTnjdQTchoU6Re9BUUGBJiOy3YMn/0ShTW6J5M0dfQ1NeDeRTTl4oIWgQMA==",
       "engines": {
         "node": ">=6.0.0"
       }
     },
+    "node_modules/punycode": {
+      "version": "2.3.1",
+      "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.3.1.tgz",
+      "integrity": "sha512-vYt7UD1U9Wg6138shLtLOvdAu+8DsC/ilFtEVHcH+wydcSpNE20AfSOduf6MkRFahL5FY7X1oU7nKVZFtfq8Fg==",
+      "engines": {
+        "node": ">=6"
+      }
+    },
     "node_modules/smtp-server": {
-      "version": "3.13.0",
-      "resolved": "https://registry.npmjs.org/smtp-server/-/smtp-server-3.13.0.tgz",
-      "integrity": "sha512-thVFqpwrHIJ25rXjXA6RYFUO35el2O+X7WJ006qMVAyFs5Ss6XGPJASg7Fh1QvT28ADIv9hGGXmgR+kaSEikwQ==",
+      "version": "3.13.2",
+      "resolved": "https://registry.npmjs.org/smtp-server/-/smtp-server-3.13.2.tgz",
+      "integrity": "sha512-MWHAmsIlrfffQ75RDruOr5DhOJF8sPeG4iSW8a0euhOjaV107OGaRo30RXmmnmoKxS1mvaL+dtSEKbgev/9YeQ==",
       "dependencies": {
         "base32.js": "0.1.0",
         "ipv6-normalize": "1.0.1",
-        "nodemailer": "6.9.4"
+        "nodemailer": "6.9.9",
+        "punycode": "2.3.1"
       },
       "engines": {
         "node": ">=12.0.0"
diff --git a/Chapter04/server-smtp/package.json b/Chapter04/server-smtp/package.json
index cdeff85..001ea7e 100644
--- a/Chapter04/server-smtp/package.json
+++ b/Chapter04/server-smtp/package.json
@@ -11,6 +11,6 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
-    "smtp-server": "^3.13.0"
+    "smtp-server": "^3.13.2"
   }
 }