diff --git a/src/class/vendor/vendor_device.c b/src/class/vendor/vendor_device.c
index 6f9b4853f..2fc0ac944 100644
--- a/src/class/vendor/vendor_device.c
+++ b/src/class/vendor/vendor_device.c
@@ -197,7 +197,7 @@ void vendord_reset(uint8_t rhport) {
 uint16_t vendord_open(uint8_t rhport, const tusb_desc_interface_t* desc_itf, uint16_t max_len) {
   TU_VERIFY(TUSB_CLASS_VENDOR_SPECIFIC == desc_itf->bInterfaceClass, 0);
   const uint8_t* p_desc = tu_desc_next(desc_itf);
-  const uint8_t* desc_end = p_desc + max_len;
+  const uint8_t* desc_end = (uint8_t const*)desc_itf + max_len;
 
   // Find available interface
   vendord_interface_t* p_vendor = NULL;