diff --git a/packages/next/build/webpack/loaders/next-middleware-ssr-loader/render.ts b/packages/next/build/webpack/loaders/next-middleware-ssr-loader/render.ts
index d38479d35f..70a3ae3596 100644
--- a/packages/next/build/webpack/loaders/next-middleware-ssr-loader/render.ts
+++ b/packages/next/build/webpack/loaders/next-middleware-ssr-loader/render.ts
@@ -1,6 +1,7 @@
 import { NextRequest } from '../../../../server/web/spec-extension/request'
 import { renderToHTML } from '../../../../server/web/render'
 import RenderResult from '../../../../server/render-result'
+import { toNodeHeaders } from '../../../../server/web/utils'
 
 const createHeaders = (args?: any) => ({
   ...args,
@@ -49,7 +50,7 @@ export function getRender({
     const req = {
       url: pathname,
       cookies,
-      headers,
+      headers: toNodeHeaders(headers),
     }
     const renderOpts = {
       ...restRenderOpts,
diff --git a/test/integration/react-streaming-and-server-components/app/pages/index.server.js b/test/integration/react-streaming-and-server-components/app/pages/index.server.js
index 1ec9eda6e3..dbb965604c 100644
--- a/test/integration/react-streaming-and-server-components/app/pages/index.server.js
+++ b/test/integration/react-streaming-and-server-components/app/pages/index.server.js
@@ -19,7 +19,7 @@ export default function Index({ header, router }) {
 
 export function getServerSideProps({ req }) {
   const { headers } = req
-  const header = headers.get(headerKey)
+  const header = headers[headerKey]
 
   return {
     props: {
diff --git a/yarn.lock b/yarn.lock
index 3308677139..40f66a8d9a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -19981,16 +19981,11 @@ webpack-bundle-analyzer@4.3.0:
     source-list-map "^2.0.0"
     source-map "~0.6.1"
 
-"webpack-sources3@npm:webpack-sources@3.2.2":
+"webpack-sources3@npm:webpack-sources@3.2.2", webpack-sources@^3.2.0, webpack-sources@^3.2.2:
   version "3.2.2"
   resolved "https://registry.yarnpkg.com/webpack-sources/-/webpack-sources-3.2.2.tgz#d88e3741833efec57c4c789b6010db9977545260"
   integrity sha512-cp5qdmHnu5T8wRg2G3vZZHoJPN14aqQ89SyQ11NpGH5zEMDCclt49rzo+MaRazk7/UeILhAI+/sEtcM+7Fr0nw==
 
-webpack-sources@^3.2.2:
-  version "3.2.2"
-  resolved "https://registry.npmjs.org/webpack-sources/-/webpack-sources-3.2.2.tgz#d88e3741833efec57c4c789b6010db9977545260"
-  integrity sha512-cp5qdmHnu5T8wRg2G3vZZHoJPN14aqQ89SyQ11NpGH5zEMDCclt49rzo+MaRazk7/UeILhAI+/sEtcM+7Fr0nw==
-
 "webpack4@npm:webpack@4.44.1":
   version "4.44.1"
   resolved "https://registry.yarnpkg.com/webpack/-/webpack-4.44.1.tgz#17e69fff9f321b8f117d1fda714edfc0b939cc21"