diff --git a/sandbox/package-lock.json b/sandbox/package-lock.json
index f8d2852..dca06fc 100644
--- a/sandbox/package-lock.json
+++ b/sandbox/package-lock.json
@@ -10,7 +10,7 @@
       "license": "Unlicense",
       "dependencies": {
         "connect": "^3.2.0",
-        "js-yaml": "^3.3.0",
+        "js-yaml": "^4.1.1",
         "oas3-tools": "^2.0.2"
       }
     },
@@ -24,6 +24,26 @@
         "js-yaml": "^3.13.1"
       }
     },
+    "node_modules/@apidevtools/json-schema-ref-parser/node_modules/argparse": {
+      "version": "1.0.10",
+      "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+      "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+      "dependencies": {
+        "sprintf-js": "~1.0.2"
+      }
+    },
+    "node_modules/@apidevtools/json-schema-ref-parser/node_modules/js-yaml": {
+      "version": "3.14.2",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+      "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
+      "dependencies": {
+        "argparse": "^1.0.7",
+        "esprima": "^4.0.0"
+      },
+      "bin": {
+        "js-yaml": "bin/js-yaml.js"
+      }
+    },
     "node_modules/@jsdevtools/ono": {
       "version": "7.1.3",
       "resolved": "https://registry.npmjs.org/@jsdevtools/ono/-/ono-7.1.3.tgz",
@@ -81,12 +101,9 @@
       "integrity": "sha1-HjRA6RXwsSA9I3SOeO3XubW0PlY="
     },
     "node_modules/argparse": {
-      "version": "1.0.10",
-      "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
-      "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
-      "dependencies": {
-        "sprintf-js": "~1.0.2"
-      }
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/argparse/-/argparse-2.0.1.tgz",
+      "integrity": "sha512-8+9WqebbFzpX9OR+Wa6O29asIogeRMzcGtAINdpMHHyAg10f05aSFVBbcEqGf/PXw1EjAZ+q2/bEBg3DvurK3Q=="
     },
     "node_modules/array-flatten": {
       "version": "1.1.1",
@@ -558,6 +575,26 @@
         "deasync": "^0.1.20"
       }
     },
+    "node_modules/express-openapi-validator/node_modules/argparse": {
+      "version": "1.0.10",
+      "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+      "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+      "dependencies": {
+        "sprintf-js": "~1.0.2"
+      }
+    },
+    "node_modules/express-openapi-validator/node_modules/js-yaml": {
+      "version": "3.14.2",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+      "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
+      "dependencies": {
+        "argparse": "^1.0.7",
+        "esprima": "^4.0.0"
+      },
+      "bin": {
+        "js-yaml": "bin/js-yaml.js"
+      }
+    },
     "node_modules/express-openapi-validator/node_modules/media-typer": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/media-typer/-/media-typer-1.1.0.tgz",
@@ -941,12 +978,11 @@
       "integrity": "sha1-ihis/Kmo9Bd+Cav8YDiTmwXR7t8="
     },
     "node_modules/js-yaml": {
-      "version": "3.14.0",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.0.tgz",
-      "integrity": "sha512-/4IbIeHcD9VMHFqDR/gQ7EdZdLimOvW2DdcxFjdyyZ9NsbS+ccrXqVWDtab/lRl5AlUqmpBx8EhPaWR+OtY17A==",
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.1.tgz",
+      "integrity": "sha512-qQKT4zQxXl8lLwBtHMWwaTcGfFOZviOJet3Oy/xmGk2gZH677CJM9EvtfdSkgWcATZhj/55JZ0rmy3myCT5lsA==",
       "dependencies": {
-        "argparse": "^1.0.7",
-        "esprima": "^4.0.0"
+        "argparse": "^2.0.1"
       },
       "bin": {
         "js-yaml": "bin/js-yaml.js"
@@ -1141,6 +1177,14 @@
         "serve-static": "^1.14.1"
       }
     },
+    "node_modules/oas3-tools/node_modules/argparse": {
+      "version": "1.0.10",
+      "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+      "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+      "dependencies": {
+        "sprintf-js": "~1.0.2"
+      }
+    },
     "node_modules/oas3-tools/node_modules/debug": {
       "version": "4.2.0",
       "resolved": "https://registry.npmjs.org/debug/-/debug-4.2.0.tgz",
@@ -1158,6 +1202,18 @@
         }
       }
     },
+    "node_modules/oas3-tools/node_modules/js-yaml": {
+      "version": "3.14.2",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+      "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
+      "dependencies": {
+        "argparse": "^1.0.7",
+        "esprima": "^4.0.0"
+      },
+      "bin": {
+        "js-yaml": "bin/js-yaml.js"
+      }
+    },
     "node_modules/oas3-tools/node_modules/ms": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
@@ -1609,7 +1665,7 @@
     "node_modules/sprintf-js": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/sprintf-js/-/sprintf-js-1.0.3.tgz",
-      "integrity": "sha1-BOaSb2YolTVPPdAVIDYzuFcpfiw="
+      "integrity": "sha512-D9cPgkvLlV3t3IzL0D0YLvGA9Ahk4PcvVwUbN0dSGr1aP0Nrt4AEnTUbuGvquEC0mA64Gqt1fzirlRs5ibXx8g=="
     },
     "node_modules/statuses": {
       "version": "1.5.0",
@@ -1712,6 +1768,25 @@
         "@jsdevtools/ono": "^7.1.3",
         "call-me-maybe": "^1.0.1",
         "js-yaml": "^3.13.1"
+      },
+      "dependencies": {
+        "argparse": {
+          "version": "1.0.10",
+          "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+          "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+          "requires": {
+            "sprintf-js": "~1.0.2"
+          }
+        },
+        "js-yaml": {
+          "version": "3.14.2",
+          "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+          "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
+          "requires": {
+            "argparse": "^1.0.7",
+            "esprima": "^4.0.0"
+          }
+        }
       }
     },
     "@jsdevtools/ono": {
@@ -1760,12 +1835,9 @@
       "integrity": "sha1-HjRA6RXwsSA9I3SOeO3XubW0PlY="
     },
     "argparse": {
-      "version": "1.0.10",
-      "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
-      "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
-      "requires": {
-        "sprintf-js": "~1.0.2"
-      }
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/argparse/-/argparse-2.0.1.tgz",
+      "integrity": "sha512-8+9WqebbFzpX9OR+Wa6O29asIogeRMzcGtAINdpMHHyAg10f05aSFVBbcEqGf/PXw1EjAZ+q2/bEBg3DvurK3Q=="
     },
     "array-flatten": {
       "version": "1.1.1",
@@ -2265,6 +2337,23 @@
         "path-to-regexp": "^6.1.0"
       },
       "dependencies": {
+        "argparse": {
+          "version": "1.0.10",
+          "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+          "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+          "requires": {
+            "sprintf-js": "~1.0.2"
+          }
+        },
+        "js-yaml": {
+          "version": "3.14.2",
+          "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+          "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
+          "requires": {
+            "argparse": "^1.0.7",
+            "esprima": "^4.0.0"
+          }
+        },
         "media-typer": {
           "version": "1.1.0",
           "resolved": "https://registry.npmjs.org/media-typer/-/media-typer-1.1.0.tgz",
@@ -2417,12 +2506,11 @@
       "integrity": "sha1-ihis/Kmo9Bd+Cav8YDiTmwXR7t8="
     },
     "js-yaml": {
-      "version": "3.14.0",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.0.tgz",
-      "integrity": "sha512-/4IbIeHcD9VMHFqDR/gQ7EdZdLimOvW2DdcxFjdyyZ9NsbS+ccrXqVWDtab/lRl5AlUqmpBx8EhPaWR+OtY17A==",
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.1.tgz",
+      "integrity": "sha512-qQKT4zQxXl8lLwBtHMWwaTcGfFOZviOJet3Oy/xmGk2gZH677CJM9EvtfdSkgWcATZhj/55JZ0rmy3myCT5lsA==",
       "requires": {
-        "argparse": "^1.0.7",
-        "esprima": "^4.0.0"
+        "argparse": "^2.0.1"
       }
     },
     "json-schema-ref-parser": {
@@ -2575,6 +2663,14 @@
         "serve-static": "^1.14.1"
       },
       "dependencies": {
+        "argparse": {
+          "version": "1.0.10",
+          "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+          "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+          "requires": {
+            "sprintf-js": "~1.0.2"
+          }
+        },
         "debug": {
           "version": "4.2.0",
           "resolved": "https://registry.npmjs.org/debug/-/debug-4.2.0.tgz",
@@ -2583,6 +2679,15 @@
             "ms": "2.1.2"
           }
         },
+        "js-yaml": {
+          "version": "3.14.2",
+          "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+          "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
+          "requires": {
+            "argparse": "^1.0.7",
+            "esprima": "^4.0.0"
+          }
+        },
         "ms": {
           "version": "2.1.2",
           "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
@@ -2934,7 +3039,7 @@
     "sprintf-js": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/sprintf-js/-/sprintf-js-1.0.3.tgz",
-      "integrity": "sha1-BOaSb2YolTVPPdAVIDYzuFcpfiw="
+      "integrity": "sha512-D9cPgkvLlV3t3IzL0D0YLvGA9Ahk4PcvVwUbN0dSGr1aP0Nrt4AEnTUbuGvquEC0mA64Gqt1fzirlRs5ibXx8g=="
     },
     "statuses": {
       "version": "1.5.0",
diff --git a/sandbox/package.json b/sandbox/package.json
index ab9d33b..4bf2ad3 100644
--- a/sandbox/package.json
+++ b/sandbox/package.json
@@ -14,7 +14,7 @@
   "private": true,
   "dependencies": {
     "connect": "^3.2.0",
-    "js-yaml": "^3.3.0",
+    "js-yaml": "^4.1.1",
     "oas3-tools": "^2.0.2"
   }
 }