diff --git a/src/main/c/src/ConfigDescriptor.c b/src/main/c/src/ConfigDescriptor.c
index 465dd1d..376a8cc 100644
--- a/src/main/c/src/ConfigDescriptor.c
+++ b/src/main/c/src/ConfigDescriptor.c
@@ -135,7 +135,7 @@ JNIEXPORT jobject JNICALL METHOD_NAME(ConfigDescriptor, extra)
 {
     struct libusb_config_descriptor *descriptor =
         unwrapConfigDescriptor(env, this);
-    return (*env)->NewDirectByteBuffer(env, descriptor,
+    return (*env)->NewDirectByteBuffer(env, (void *) descriptor->extra,
         descriptor->extra_length);
 }
 
diff --git a/src/main/c/src/EndpointDescriptor.c b/src/main/c/src/EndpointDescriptor.c
index b8c72dd..109795a 100644
--- a/src/main/c/src/EndpointDescriptor.c
+++ b/src/main/c/src/EndpointDescriptor.c
@@ -129,7 +129,7 @@ JNIEXPORT jobject JNICALL METHOD_NAME(EndpointDescriptor, extra)
 {
     struct libusb_endpoint_descriptor *descriptor =
         unwrapEndpointDescriptor(env, this);
-    return (*env)->NewDirectByteBuffer(env, descriptor,
+    return (*env)->NewDirectByteBuffer(env, (void *) descriptor->extra,
         descriptor->extra_length);
 }
 
diff --git a/src/main/c/src/InterfaceDescriptor.c b/src/main/c/src/InterfaceDescriptor.c
index c5a951e..4ad67ec 100644
--- a/src/main/c/src/InterfaceDescriptor.c
+++ b/src/main/c/src/InterfaceDescriptor.c
@@ -155,7 +155,7 @@ JNIEXPORT jobject JNICALL METHOD_NAME(InterfaceDescriptor, extra)
 {
     struct libusb_interface_descriptor *descriptor =
         unwrapInterfaceDescriptor(env, this);
-    return (*env)->NewDirectByteBuffer(env, descriptor,
+    return (*env)->NewDirectByteBuffer(env, (void *) descriptor->extra,
         descriptor->extra_length);
 }