diff --git a/yarn.lock b/yarn.lock
index 3a26bb5..ac8b402 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -22,6 +22,10 @@ ansi-styles@^3.1.0:
   dependencies:
     color-convert "^1.9.0"
 
+async-limiter@~1.0.0:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.1.tgz#dd379e94f0db8310b08291f9d64c3209766617fd"
+
 balanced-match@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/balanced-match/-/balanced-match-1.0.0.tgz#89b4d199ab2bee49de164ea02b89ce462d71b767"
@@ -470,8 +474,8 @@ rimraf@^2.6.1:
     glob "^7.0.5"
 
 safe-buffer@~5.1.0, safe-buffer@~5.1.1:
-  version "5.1.1"
-  resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.1.1.tgz#893312af69b2123def71f57889001671eeb2c853"
+  version "5.1.2"
+  resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.1.2.tgz#991ec69d296e0313747d59bdfd2b745c35f8828d"
 
 "semver@2 || 3 || 4 || 5":
   version "5.4.1"
@@ -561,8 +565,8 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
 
 ultron@~1.1.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/ultron/-/ultron-1.1.0.tgz#b07a2e6a541a815fc6a34ccd4533baec307ca864"
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/ultron/-/ultron-1.1.1.tgz#9fe1536a10a664a65266a1e3ccf85fd36302bc9c"
 
 util-deprecate@~1.0.1:
   version "1.0.2"
@@ -597,9 +601,10 @@ wrappy@1:
   resolved "https://registry.yarnpkg.com/wrappy/-/wrappy-1.0.2.tgz#b5243d8f3ec1aa35f1364605bc0d1036e30ab69f"
 
 ws@^3.0.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/ws/-/ws-3.1.0.tgz#8afafecdeab46d572e5397ee880739367aa2f41c"
+  version "3.3.3"
+  resolved "https://registry.yarnpkg.com/ws/-/ws-3.3.3.tgz#f1cf84fe2d5e901ebce94efaece785f187a228f2"
   dependencies:
+    async-limiter "~1.0.0"
     safe-buffer "~5.1.0"
     ultron "~1.1.0"