diff --git a/benchmark/child_process/child-process-exec-stdout.js b/benchmark/child_process/child-process-exec-stdout.js
index 6194f66b55d987..f48e8257e6c421 100644
--- a/benchmark/child_process/child-process-exec-stdout.js
+++ b/benchmark/child_process/child-process-exec-stdout.js
@@ -1,7 +1,7 @@
 'use strict';
 const common = require('../common.js');
 
-var messagesLength = [64, 256, 1024, 4096];
+const messagesLength = [64, 256, 1024, 4096];
 // Windows does not support that long arguments
 if (process.platform !== 'win32')
   messagesLength.push(32768);
diff --git a/benchmark/child_process/child-process-read.js b/benchmark/child_process/child-process-read.js
index b0128eb7969056..58f016c764ae0b 100644
--- a/benchmark/child_process/child-process-read.js
+++ b/benchmark/child_process/child-process-read.js
@@ -2,7 +2,7 @@
 const common = require('../common.js');
 const os = require('os');
 
-var messagesLength = [64, 256, 1024, 4096];
+const messagesLength = [64, 256, 1024, 4096];
 // Windows does not support that long arguments
 if (os.platform() !== 'win32')
   messagesLength.push(32768);
diff --git a/test/parallel/test-child-process-exec-data-buffer.js b/test/parallel/test-child-process-exec-data-buffer.js
new file mode 100644
index 00000000000000..0854203d0ef335
--- /dev/null
+++ b/test/parallel/test-child-process-exec-data-buffer.js
@@ -0,0 +1,15 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const exec = require('child_process').exec;
+
+const expectedCalls = 2;
+
+const cb = common.mustCall((data) => {
+  assert(data instanceof Buffer);
+}, expectedCalls);
+
+const command = common.isWindows ? 'dir' : 'ls';
+exec(command).stdout.on('data', cb);
+
+exec('fhqwhgads').stderr.on('data', cb);