diff --git a/src/network/kernel/qnetworkinterface_win.cpp b/src/network/kernel/qnetworkinterface_win.cpp
index 857e40215c..150553f673 100644
--- a/src/network/kernel/qnetworkinterface_win.cpp
+++ b/src/network/kernel/qnetworkinterface_win.cpp
@@ -151,7 +151,7 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
         else if (ptr->IfIndex != 0)
             iface->index = ptr->IfIndex;
 
-        iface->mtu = ptr->Mtu;
+        iface->mtu = qMin<qint64>(ptr->Mtu, INT_MAX);
         iface->flags = QNetworkInterface::CanBroadcast;
         if (ptr->OperStatus == IfOperStatusUp)
             iface->flags |= QNetworkInterface::IsUp | QNetworkInterface::IsRunning;
diff --git a/tests/auto/network/kernel/qnetworkinterface/tst_qnetworkinterface.cpp b/tests/auto/network/kernel/qnetworkinterface/tst_qnetworkinterface.cpp
index ae5082fecb..93dd73d64a 100644
--- a/tests/auto/network/kernel/qnetworkinterface/tst_qnetworkinterface.cpp
+++ b/tests/auto/network/kernel/qnetworkinterface/tst_qnetworkinterface.cpp
@@ -184,6 +184,8 @@ void tst_QNetworkInterface::consistencyCheck()
         if (iface.index())
             interfaceIndexes << iface.index();
 
+        QVERIFY(iface.maxTransmissionUnit() >= 0);
+
         const QList<QNetworkAddressEntry> addresses = iface.addressEntries();
         for (auto entry : addresses) {
             QVERIFY(entry.ip().protocol() != QAbstractSocket::UnknownNetworkLayerProtocol);