1 files changed, 2 insertions, 1 deletions
diff --git a/lib/child_process.js b/lib/child_process.js
index f2c1a0c237..00d1bfc57d 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -504,7 +504,8 @@ function normalizeSpawnArguments(file, args, options) {
   var env = options.env || process.env;
   var envPairs = [];
 
-  for (const key of Object.keys(env)) {
+  // Prototype values are intentionally included.
+  for (var key in env) {
     const value = env[key];
     if (value !== undefined) {
       envPairs.push(`${key}=${value}`);