diff --git a/lib/Controller/WopiController.php b/lib/Controller/WopiController.php
index d1d2efded2..7f704eccd0 100644
--- a/lib/Controller/WopiController.php
+++ b/lib/Controller/WopiController.php
@@ -486,10 +486,10 @@ public function putFile($fileId,
 			$content = fopen('php://input', 'rb');
 
 			$freespace = $file->getParent()->getFreeSpace();
-			$contentLength = $this->request->getHeader('CONTENT_LENGTH');
+			$contentLength = (int)$this->request->getHeader('Content-Length');
 
 			try {
-				if ($contentLength > $freespace) {
+				if ($freespace >= 0 && $contentLength > $freespace) {
 					throw new \Exception('Not enough storage');
 				}
 				$this->wrappedFilesystemOperation($wopi, function () use ($file, $content) {