diff --git a/src/Symfony/Component/Mailer/Transport/SendmailTransport.php b/src/Symfony/Component/Mailer/Transport/SendmailTransport.php
index 3add460ebcf89..774c0e5631a13 100644
--- a/src/Symfony/Component/Mailer/Transport/SendmailTransport.php
+++ b/src/Symfony/Component/Mailer/Transport/SendmailTransport.php
@@ -114,7 +114,7 @@ protected function doSend(SentMessage $message): void
         $this->stream->setCommand($command);
         $this->stream->initialize();
         foreach ($chunks as $chunk) {
-            $this->stream->write($chunk);
+            $this->stream->write($chunk, false);
         }
         $this->stream->flush();
         $this->stream->terminate();