Clone message to prevent header alteration persisting in RoundRobinTransport

jnoordsij · jnoordsij · commit 251bf3a4aca6 · 2025-06-18T10:27:05.000+02:00
diff --git a/src/Symfony/Component/Mailer/Transport/RoundRobinTransport.php b/src/Symfony/Component/Mailer/Transport/RoundRobinTransport.php
@@ -52,7 +52,7 @@ public function send(RawMessage $message, ?Envelope $envelope = null): ?SentMess
 
         while ($transport = $this->getNextTransport()) {
             try {
-                return $transport->send($message, $envelope);
+                return $transport->send(clone $message, $envelope);
             } catch (TransportExceptionInterface $e) {
                 $exception ??= new TransportException('All transports failed.');
                 $exception->appendDebug(sprintf("Transport \"%s\": %s\n", $transport, $e->getDebug()));
