diff --git a/packages/gatsby/package.json b/packages/gatsby/package.json
index 6ae8c490a1cb7..383c054e489c1 100644
--- a/packages/gatsby/package.json
+++ b/packages/gatsby/package.json
@@ -46,7 +46,7 @@
     "express-graphql": "^0.6.6",
     "extract-text-webpack-plugin": "^1.0.1",
     "file-loader": "^0.9.0",
-    "flat": "^2.0.1",
+    "flat": "^5.0.1",
     "friendly-errors-webpack-plugin": "^1.6.1",
     "front-matter": "^2.1.0",
     "fs-extra": "^4.0.1",
diff --git a/yarn.lock b/yarn.lock
index d5ef9bb00aa65..7128431717e34 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4594,18 +4594,16 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
-flat@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/flat/-/flat-2.0.1.tgz#70e29188a74be0c3c89409eed1fa9577907ae32f"
-  dependencies:
-    is-buffer "~1.1.2"
-
 flat@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/flat/-/flat-4.0.0.tgz#3abc7f3b588e64ce77dc42fd59aa35806622fea8"
   dependencies:
     is-buffer "~1.1.5"
 
+flat@^5.0.1:
+  version "5.0.1"
+  resolved "https://registry.yarnpkg.com/flat/-/flat-5.0.1.tgz#ed5f357d6c9e754d1fdc392b1d570426f8e013c2"
+
 flatten@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/flatten/-/flatten-1.0.2.tgz#dae46a9d78fbe25292258cc1e780a41d95c03782"
@@ -5855,7 +5853,7 @@ is-binary-path@^1.0.0:
   dependencies:
     binary-extensions "^1.0.0"
 
-is-buffer@^1.0.2, is-buffer@^1.1.4, is-buffer@^1.1.5, is-buffer@~1.1.1, is-buffer@~1.1.2, is-buffer@~1.1.5:
+is-buffer@^1.0.2, is-buffer@^1.1.4, is-buffer@^1.1.5, is-buffer@~1.1.1, is-buffer@~1.1.5:
   version "1.1.5"
   resolved "https://registry.yarnpkg.com/is-buffer/-/is-buffer-1.1.5.tgz#1f3b26ef613b214b88cbca23cc6c01d87961eecc"