diff --git a/src/spawn_sync.cc b/src/spawn_sync.cc
index fbcb1d4f02c905..264b6709ff1260 100644
--- a/src/spawn_sync.cc
+++ b/src/spawn_sync.cc
@@ -50,9 +50,7 @@ using v8::String;
 using v8::Value;
 
 
-SyncProcessOutputBuffer::SyncProcessOutputBuffer()
-    : used_(0),
-      next_(nullptr) {
+SyncProcessOutputBuffer::SyncProcessOutputBuffer() {
 }
 
 
diff --git a/src/spawn_sync.h b/src/spawn_sync.h
index adb2618cc5f404..397e62b9d2c0d9 100644
--- a/src/spawn_sync.h
+++ b/src/spawn_sync.h
@@ -56,9 +56,9 @@ class SyncProcessOutputBuffer {
  private:
   // Use unsigned int because that's what `uv_buf_init` takes.
   mutable char data_[kBufferSize];
-  unsigned int used_;
+  unsigned int used_ = 0;
 
-  SyncProcessOutputBuffer* next_;
+  SyncProcessOutputBuffer* next_ = nullptr;
 };