diff --git a/package.json b/package.json
index d9812ae..c32a906 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "@types/node": "^6.0.0",
     "@types/q": "^1.0.3",
     "all-contributors-cli": "^4.10.1",
-    "async": "^2.6.0",
+    "async": "^2.6.4",
     "ava": "^0.25.0",
     "babel-core": "^6.26.0",
     "babel-loader": "^7.1.2",
diff --git a/yarn.lock b/yarn.lock
index a1b84de..b7ca416 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -570,19 +570,12 @@ async@^1.4.0:
   resolved "https://registry.yarnpkg.com/async/-/async-1.5.2.tgz#ec6a61ae56480c0c3cb241c95618e20892f9672a"
   integrity sha1-7GphrlZIDAw8skHJVhjiCJL5Zyo=
 
-async@^2.0.0-rc.1, async@^2.1.2:
-  version "2.6.1"
-  resolved "https://registry.yarnpkg.com/async/-/async-2.6.1.tgz#b245a23ca71930044ec53fa46aa00a3e87c6a610"
-  integrity sha512-fNEiL2+AZt6AlAw/29Cr0UDe4sRAHCpEHh54WMz+Bb7QfNcFw4h3loofyJpLeQs4Yx7yuqu/2dLgM5hKOs6HlQ==
+async@^2.0.0-rc.1, async@^2.1.2, async@^2.6.4:
+  version "2.6.4"
+  resolved "https://registry.yarnpkg.com/async/-/async-2.6.4.tgz#706b7ff6084664cd7eae713f6f965433b5504221"
+  integrity sha512-mzo5dfJYwAn29PeiJ0zvwTo04zj8HDJj0Mn8TD7sno7q12prdbnasKJHhkm2c1LgrhlJ0teaea8860oxi51mGA==
   dependencies:
-    lodash "^4.17.10"
-
-async@^2.6.0:
-  version "2.6.0"
-  resolved "https://registry.yarnpkg.com/async/-/async-2.6.0.tgz#61a29abb6fcc026fea77e56d1c6ec53a795951f4"
-  integrity sha512-xAfGg1/NTLBBKlHFmnd7PlmUW9KhVQIUuSrYem9xzFUZy13ScvtyGGejaae9iAVRiRq9+Cx7DPFaAAhCpyxyPw==
-  dependencies:
-    lodash "^4.14.0"
+    lodash "^4.17.14"
 
 asynckit@^0.4.0:
   version "0.4.0"
@@ -5820,20 +5813,10 @@ lodash.toplainobject@^3.0.0:
     lodash._basecopy "^3.0.0"
     lodash.keysin "^3.0.0"
 
-lodash@^4.0.0, lodash@^4.2.1:
-  version "4.17.5"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.5.tgz#99a92d65c0272debe8c96b6057bc8fbfa3bed511"
-  integrity sha512-svL3uiZf1RwhH+cWrfZn3A4+U58wbP0tGVTLQPbjplZxZ8ROD9VLuNgsRniTlLe7OlSqR79RUehXgpBW/s0IQw==
-
-lodash@^4.11.2, lodash@^4.14.0, lodash@^4.17.10, lodash@^4.3.0:
-  version "4.17.10"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.10.tgz#1b7793cf7259ea38fb3661d4d38b3260af8ae4e7"
-  integrity sha512-UejweD1pDoXu+AD825lWwp4ZGtSwgnpZxb3JDViD7StjQz+Nb/6l093lx4OQ0foGWNRoc19mWy7BzL+UAK2iVg==
-
-lodash@^4.17.4:
-  version "4.17.4"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
-  integrity sha1-eCA6TRwyiuHYbcpkYONptX9AVa4=
+lodash@^4.0.0, lodash@^4.11.2, lodash@^4.17.14, lodash@^4.17.4, lodash@^4.2.1, lodash@^4.3.0:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
+  integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
 
 log-update@^1.0.2:
   version "1.0.2"