diff --git a/Neos.Flow/Classes/Mvc/ActionResponse.php b/Neos.Flow/Classes/Mvc/ActionResponse.php
index 8671eda844..32007f53e4 100644
--- a/Neos.Flow/Classes/Mvc/ActionResponse.php
+++ b/Neos.Flow/Classes/Mvc/ActionResponse.php
@@ -198,7 +198,9 @@ public function getHttpHeader(string $headerName)
     public function getContent(): string
     {
         $content = $this->content->getContents();
-        $this->content->rewind();
+        if ($this->content->isSeekable()) {
+            $this->content->rewind();
+        }
         return $content;
     }