diff --git a/packages/next/build/entries.ts b/packages/next/build/entries.ts
index dc87eb2d9a255821203bd1f237973326ece67ded..4d6c942751af1ace19573d881046147d8a074a58 100644
--- a/packages/next/build/entries.ts
+++ b/packages/next/build/entries.ts
@@ -92,7 +92,10 @@ export function createEntrypoints(
         })
       : '',
     previewProps: JSON.stringify(previewMode),
-    loadedEnvFiles: JSON.stringify(loadedEnvFiles),
+    // base64 encode to make sure contents don't break webpack URL loading
+    loadedEnvFiles: Buffer.from(JSON.stringify(loadedEnvFiles)).toString(
+      'base64'
+    ),
   }
 
   Object.keys(pages).forEach((page) => {
diff --git a/packages/next/build/webpack/loaders/next-serverless-loader.ts b/packages/next/build/webpack/loaders/next-serverless-loader.ts
index b78825641936b9e19a325c81493ab108dfcad231..3cc4d959dcfb6aefe325eeb2953ec84a6705a750 100644
--- a/packages/next/build/webpack/loaders/next-serverless-loader.ts
+++ b/packages/next/build/webpack/loaders/next-serverless-loader.ts
@@ -90,7 +90,7 @@ const nextServerlessLoader: loader.Loader = function () {
     : ''
   const envLoading = `
     const { processEnv } = require('next/dist/lib/load-env-config')
-    processEnv(${loadedEnvFiles})
+    processEnv(${Buffer.from(loadedEnvFiles, 'base64').toString()})
   `
 
   const runtimeConfigImports = runtimeConfig
diff --git a/test/integration/env-config/app/.env b/test/integration/env-config/app/.env
index ea9c02f8cce6749844db7e1715ceb9eaf14af534..d50cde61838c9186e7a7a18ff3442b0efd50ed67 100644
--- a/test/integration/env-config/app/.env
+++ b/test/integration/env-config/app/.env
@@ -1,4 +1,4 @@
-PROCESS_ENV_KEY=env
+PROCESS_ENV_KEY="env"
 ENV_FILE_KEY=env
 ENV_FILE_LOCAL_OVERRIDE_TEST=env
 ENV_FILE_DEVELOPMENT_OVERRIDE_TEST=env
@@ -10,4 +10,5 @@ ENV_FILE_TEST_LOCAL_OVERRIDEOVERRIDE_TEST=env
 NEXT_PUBLIC_TEST_DEST=another
 ENV_FILE_EXPANDED=$ENV_FILE_KEY
 ENV_FILE_EXPANDED_CONCAT=hello-${ENV_FILE_KEY}
-ENV_FILE_EXPANDED_ESCAPED=\$ENV_FILE_KEY
\ No newline at end of file
+ENV_FILE_EXPANDED_ESCAPED=\$ENV_FILE_KEY
+ENV_FILE_KEY_EXCLAMATION="hello!"
\ No newline at end of file
diff --git a/test/integration/env-config/app/pages/api/all.js b/test/integration/env-config/app/pages/api/all.js
index 61d66efb0e82556e5f84c6f7541a638000c5ca15..71c4968c8cc6cab3a45a57a9c23a6db843f4aa4f 100644
--- a/test/integration/env-config/app/pages/api/all.js
+++ b/test/integration/env-config/app/pages/api/all.js
@@ -18,6 +18,7 @@ const variables = [
   'ENV_FILE_EXPANDED',
   'ENV_FILE_EXPANDED_CONCAT',
   'ENV_FILE_EXPANDED_ESCAPED',
+  'ENV_FILE_KEY_EXCLAMATION',
 ]
 
 const items = {}
diff --git a/test/integration/env-config/app/pages/index.js b/test/integration/env-config/app/pages/index.js
index c3e693267750cbdba998d42ae91bfde8972dd1eb..da92cea371dfa48a8c03f1b1c1fb6219818f4357 100644
--- a/test/integration/env-config/app/pages/index.js
+++ b/test/integration/env-config/app/pages/index.js
@@ -18,6 +18,7 @@ const variables = [
   'ENV_FILE_EXPANDED',
   'ENV_FILE_EXPANDED_CONCAT',
   'ENV_FILE_EXPANDED_ESCAPED',
+  'ENV_FILE_KEY_EXCLAMATION',
 ]
 
 export async function getStaticProps() {
diff --git a/test/integration/env-config/app/pages/some-ssg.js b/test/integration/env-config/app/pages/some-ssg.js
index c3e693267750cbdba998d42ae91bfde8972dd1eb..da92cea371dfa48a8c03f1b1c1fb6219818f4357 100644
--- a/test/integration/env-config/app/pages/some-ssg.js
+++ b/test/integration/env-config/app/pages/some-ssg.js
@@ -18,6 +18,7 @@ const variables = [
   'ENV_FILE_EXPANDED',
   'ENV_FILE_EXPANDED_CONCAT',
   'ENV_FILE_EXPANDED_ESCAPED',
+  'ENV_FILE_KEY_EXCLAMATION',
 ]
 
 export async function getStaticProps() {
diff --git a/test/integration/env-config/app/pages/some-ssp.js b/test/integration/env-config/app/pages/some-ssp.js
index 10cfebf896b21b3fbb426d2491200e7230989d8e..62db07bb4223ab547ac96cdd995d5f01fc0bde64 100644
--- a/test/integration/env-config/app/pages/some-ssp.js
+++ b/test/integration/env-config/app/pages/some-ssp.js
@@ -18,6 +18,7 @@ const variables = [
   'ENV_FILE_EXPANDED',
   'ENV_FILE_EXPANDED_CONCAT',
   'ENV_FILE_EXPANDED_ESCAPED',
+  'ENV_FILE_KEY_EXCLAMATION',
 ]
 
 export async function getServerSideProps() {
diff --git a/test/integration/env-config/test/index.test.js b/test/integration/env-config/test/index.test.js
index 2ae15211a88c88b7a8518cff95a271a5242daef7..3c3d7222fccafc93b541c50f5812679196d84abe 100644
--- a/test/integration/env-config/test/index.test.js
+++ b/test/integration/env-config/test/index.test.js
@@ -50,6 +50,7 @@ const runTests = (mode = 'dev') => {
     expect(data.ENV_FILE_EXPANDED).toBe('env')
     expect(data.ENV_FILE_EXPANDED_CONCAT).toBe('hello-env')
     expect(data.ENV_FILE_EXPANDED_ESCAPED).toBe('$ENV_FILE_KEY')
+    expect(data.ENV_FILE_KEY_EXCLAMATION).toBe('hello!')
   }
 
   it('should have process environment override .env', async () => {