diff --git a/packages/server/src/uwebsockets.ts b/packages/server/src/uwebsockets.ts
index ea9124d9558..f5da7a6febf 100644
--- a/packages/server/src/uwebsockets.ts
+++ b/packages/server/src/uwebsockets.ts
@@ -43,7 +43,7 @@ export function getRequestFromUWSRequest({ req, res, fetchAPI }: GetRequestFromU
     });
     let multipleChunks = false;
     res.onData(function (ab, isLast) {
-      const chunk = Buffer.from(chunk, 0, chunk.byteLength);
+      const chunk = Buffer.from(ab, 0, ab.byteLength);
       if (!multipleChunks && isLast) {
         readable.push(chunk);
       } else {