diff --git a/HISTORY.md b/HISTORY.md
index 8838d37..3c7fa6f 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -2,6 +2,12 @@
 
 https://github.com/josdejong/jsoneditor
 
+
+## not yet published, version 8.6.5
+
+- Update ace editor to `v1.4.9`.
+
+
 ## 2020-03-29, version 8.6.4
 
 - Fix #921: `sortObjectKeys` emits `onChange` events.
diff --git a/package-lock.json b/package-lock.json
index 8fc081c..b0dbcd7 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1131,9 +1131,9 @@
       "dev": true
     },
     "ace-builds": {
-      "version": "1.4.8",
-      "resolved": "https://registry.npmjs.org/ace-builds/-/ace-builds-1.4.8.tgz",
-      "integrity": "sha512-8ZVAxwyCGAxQX8mOp9imSXH0hoSPkGfy8igJy+WO/7axL30saRhKgg1XPACSmxxPA7nfHVwM+ShWXT+vKsNuFg=="
+      "version": "1.4.9",
+      "resolved": "https://registry.npmjs.org/ace-builds/-/ace-builds-1.4.9.tgz",
+      "integrity": "sha512-6I+uUDsj9AKu45VgJvloplr2DtGXRxsXNfdV9TypDkDi9MBiIV+oRNFJAf0g1b42Er3fgaVzMbLBxCeJQYNtSA=="
     },
     "acorn": {
       "version": "7.1.1",
@@ -2799,6 +2799,14 @@
       "dev": true,
       "requires": {
         "webidl-conversions": "^5.0.0"
+      },
+      "dependencies": {
+        "webidl-conversions": {
+          "version": "5.0.0",
+          "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-5.0.0.tgz",
+          "integrity": "sha512-VlZwKPCkYKxQgeSbH5EyngOmRp7Ww7I9rQLERETtf5ofd9pGeswWiOtogpEO850jziPRarreGxn5QIiTqpb2wA==",
+          "dev": true
+        }
       }
     },
     "duplexify": {
@@ -5789,9 +5797,9 @@
       "dev": true
     },
     "jsdom": {
-      "version": "16.2.1",
-      "resolved": "https://registry.npmjs.org/jsdom/-/jsdom-16.2.1.tgz",
-      "integrity": "sha512-3p0gHs5EfT7PxW9v8Phz3mrq//4Dy8MQenU/PoKxhdT+c45S7NjIjKbGT3Ph0nkICweE1r36+yaknXA5WfVNAg==",
+      "version": "16.2.2",
+      "resolved": "https://registry.npmjs.org/jsdom/-/jsdom-16.2.2.tgz",
+      "integrity": "sha512-pDFQbcYtKBHxRaP55zGXCJWgFHkDAYbKcsXEK/3Icu9nKYZkutUXfLBwbD+09XDutkYSHcgfQLZ0qvpAAm9mvg==",
       "dev": true,
       "requires": {
         "abab": "^2.0.3",
@@ -5814,11 +5822,11 @@
         "tough-cookie": "^3.0.1",
         "w3c-hr-time": "^1.0.2",
         "w3c-xmlserializer": "^2.0.0",
-        "webidl-conversions": "^5.0.0",
+        "webidl-conversions": "^6.0.0",
         "whatwg-encoding": "^1.0.5",
         "whatwg-mimetype": "^2.3.0",
         "whatwg-url": "^8.0.0",
-        "ws": "^7.2.1",
+        "ws": "^7.2.3",
         "xml-name-validator": "^3.0.0"
       },
       "dependencies": {
@@ -6479,9 +6487,9 @@
       }
     },
     "mkdirp": {
-      "version": "1.0.3",
-      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-1.0.3.tgz",
-      "integrity": "sha512-6uCP4Qc0sWsgMLy1EOqqS/3rjDHOEnsStVr/4vtAIK2Y5i2kA7lFFejYrpIyiN9w0pYf4ckeCYT9f1r1P9KX5g==",
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-1.0.4.tgz",
+      "integrity": "sha512-vVqVZQyf3WLx2Shd0qJ9xuvqgAyKPLAiqITEtqW0oIUjzo3PePDd6fW9iFz30ef7Ysp/oiWqbhszeGWW2T6Gzw==",
       "dev": true
     },
     "mobius1-selectr": {
@@ -9712,9 +9720,9 @@
       }
     },
     "webidl-conversions": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-5.0.0.tgz",
-      "integrity": "sha512-VlZwKPCkYKxQgeSbH5EyngOmRp7Ww7I9rQLERETtf5ofd9pGeswWiOtogpEO850jziPRarreGxn5QIiTqpb2wA==",
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-6.0.0.tgz",
+      "integrity": "sha512-jTZAeJnc6D+yAOjygbJOs33kVQIk5H6fj9SFDOhIKjsf9HiAzL/c+tAJsc8ASWafvhNkH+wJZms47pmajkhatA==",
       "dev": true
     },
     "webpack": {
@@ -9823,6 +9831,14 @@
         "lodash.sortby": "^4.7.0",
         "tr46": "^2.0.0",
         "webidl-conversions": "^5.0.0"
+      },
+      "dependencies": {
+        "webidl-conversions": {
+          "version": "5.0.0",
+          "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-5.0.0.tgz",
+          "integrity": "sha512-VlZwKPCkYKxQgeSbH5EyngOmRp7Ww7I9rQLERETtf5ofd9pGeswWiOtogpEO850jziPRarreGxn5QIiTqpb2wA==",
+          "dev": true
+        }
       }
     },
     "which": {
diff --git a/package.json b/package.json
index 92d46e9..cb65a25 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,7 @@
     "prepublishOnly": "npm test && npm run build"
   },
   "dependencies": {
-    "ace-builds": "^1.4.8",
+    "ace-builds": "^1.4.9",
     "ajv": "^6.12.0",
     "javascript-natural-sort": "^0.7.1",
     "jmespath": "^0.15.0",
@@ -47,9 +47,9 @@
     "gulp-clean-css": "^4.3.0",
     "gulp-concat-css": "^3.1.0",
     "gulp-sass": "^4.0.2",
-    "jsdom": "^16.2.1",
+    "jsdom": "^16.2.2",
     "json-loader": "^0.5.7",
-    "mkdirp": "^1.0.3",
+    "mkdirp": "^1.0.4",
     "mocha": "^7.1.1",
     "standard": "^14.3.3",
     "uglify-js": "^3.8.1",