diff --git a/bigcode-astgen/javascript/package.json b/bigcode-astgen/javascript/package.json
index 1c9214b..ce0c2dd 100644
--- a/bigcode-astgen/javascript/package.json
+++ b/bigcode-astgen/javascript/package.json
@@ -8,7 +8,7 @@
   },
   "dependencies": {
     "acorn": "^5.1.2",
-    "async": "^2.5.0",
+    "async": "^2.6.4",
     "glob": "^7.1.2",
     "yargs": "10.0.3"
   },
diff --git a/bigcode-astgen/javascript/yarn.lock b/bigcode-astgen/javascript/yarn.lock
index 1fbbaee..9e03c96 100644
--- a/bigcode-astgen/javascript/yarn.lock
+++ b/bigcode-astgen/javascript/yarn.lock
@@ -75,11 +75,11 @@ assertion-error@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/assertion-error/-/assertion-error-1.0.2.tgz#13ca515d86206da0bac66e834dd397d87581094c"
 
-async@^2.5.0:
-  version "2.5.0"
-  resolved "https://registry.yarnpkg.com/async/-/async-2.5.0.tgz#843190fd6b7357a0b9e1c956edddd5ec8462b54d"
+async@^2.6.4:
+  version "2.6.4"
+  resolved "https://registry.yarnpkg.com/async/-/async-2.6.4.tgz#706b7ff6084664cd7eae713f6f965433b5504221"
   dependencies:
-    lodash "^4.14.0"
+    lodash "^4.17.14"
 
 babel-code-frame@^6.22.0:
   version "6.26.0"
@@ -696,9 +696,9 @@ lodash.keys@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
-lodash@^4.14.0, lodash@^4.17.4, lodash@^4.3.0:
-  version "4.17.4"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
+lodash@^4.17.14, lodash@^4.17.4, lodash@^4.3.0:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
 
 lru-cache@^4.0.1:
   version "4.1.1"