diff --git a/package-lock.json b/package-lock.json
index e31a69bcbb..67851f0ffb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -67,7 +67,7 @@
         "ts-node": "^10.9.2",
         "tsd": "^0.31.1",
         "typescript": "^5.5.3",
-        "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.30.0",
+        "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.48.0",
         "wdio-geckodriver-service": "^5.0.2"
       }
     },
@@ -14207,9 +14207,10 @@
       }
     },
     "node_modules/uWebSockets.js": {
-      "version": "20.30.0",
-      "resolved": "git+ssh://git@github.com/uNetworking/uWebSockets.js.git#d39d4181daf5b670d44cbc1b18f8c28c85fd4142",
-      "dev": true
+      "version": "20.48.0",
+      "resolved": "git+ssh://git@github.com/uNetworking/uWebSockets.js.git#51ae1d1fd92dff77cbbdc7c431021f85578da1a6",
+      "dev": true,
+      "license": "Apache-2.0"
     },
     "node_modules/v8-compile-cache-lib": {
       "version": "3.0.1",
diff --git a/package.json b/package.json
index d10a0029bf..5ce5b3fc8f 100644
--- a/package.json
+++ b/package.json
@@ -68,7 +68,7 @@
     "ts-node": "^10.9.2",
     "tsd": "^0.31.1",
     "typescript": "^5.5.3",
-    "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.30.0",
+    "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.48.0",
     "wdio-geckodriver-service": "^5.0.2"
   }
 }
diff --git a/packages/engine.io/test/common.js b/packages/engine.io/test/common.js
index 72b254a328..136395fbbb 100644
--- a/packages/engine.io/test/common.js
+++ b/packages/engine.io/test/common.js
@@ -4,6 +4,17 @@ const { Socket } =
     ? require("engine.io-client-v3")
     : require("engine.io-client");
 
+switch (process.env.EIO_WS_ENGINE) {
+  case "uws":
+    console.log(
+      "[WARN] testing with uWebSockets.js instead of Node.js built-in HTTP server",
+    );
+    break;
+  case "eiows":
+    console.log("[WARN] testing with eiows instead of ws");
+    break;
+}
+
 /**
  * Listen shortcut that fires a callback on an ephemeral port.
  */
diff --git a/packages/engine.io/test/server.js b/packages/engine.io/test/server.js
index 35b1988357..898e53f673 100644
--- a/packages/engine.io/test/server.js
+++ b/packages/engine.io/test/server.js
@@ -817,7 +817,7 @@ describe("server", () => {
           .end((err, res) => {
             if (process.env.EIO_WS_ENGINE === "uws") {
               expect(err).to.not.be(null);
-              expect(err.message).to.be("socket hang up");
+              expect(err.status).to.be(404);
             } else {
               expect(err).to.be(null);
               // this should not work, but it is kept for backward-compatibility
diff --git a/packages/socket.io/lib/uws.ts b/packages/socket.io/lib/uws.ts
index 89a6bf7d33..14bcc0aebb 100644
--- a/packages/socket.io/lib/uws.ts
+++ b/packages/socket.io/lib/uws.ts
@@ -135,25 +135,27 @@ export function serveFile(res /* : HttpResponse */, filepath: string) {
   const onDataChunk = (chunk: Buffer) => {
     const arrayBufferChunk = toArrayBuffer(chunk);
 
-    const lastOffset = res.getWriteOffset();
-    const [ok, done] = res.tryEnd(arrayBufferChunk, size);
+    res.cork(() => {
+      const lastOffset = res.getWriteOffset();
+      const [ok, done] = res.tryEnd(arrayBufferChunk, size);
 
-    if (!done && !ok) {
-      readStream.pause();
+      if (!done && !ok) {
+        readStream.pause();
 
-      res.onWritable((offset) => {
-        const [ok, done] = res.tryEnd(
-          arrayBufferChunk.slice(offset - lastOffset),
-          size,
-        );
+        res.onWritable((offset) => {
+          const [ok, done] = res.tryEnd(
+            arrayBufferChunk.slice(offset - lastOffset),
+            size,
+          );
 
-        if (!done && ok) {
-          readStream.resume();
-        }
+          if (!done && ok) {
+            readStream.resume();
+          }
 
-        return ok;
-      });
-    }
+          return ok;
+        });
+      }
+    });
   };
 
   res.onAborted(destroyReadStream);