diff --git a/third_party/libusb/src/libusb/libusbi.h b/third_party/libusb/src/libusb/libusbi.h
index 289d43fd2911c..970d2491acdb8 100644
--- a/third_party/libusb/src/libusb/libusbi.h
+++ b/third_party/libusb/src/libusb/libusbi.h
@@ -39,6 +39,20 @@
 #include "libusb.h"
 #include "version.h"
 
+/* Attribute to ensure that a structure member is aligned to a natural
+ * pointer alignment. Used for os_priv member. */
+#if defined(_MSC_VER)
+#if defined(_WIN64)
+#define PTR_ALIGNED __declspec(align(8))
+#else
+#define PTR_ALIGNED __declspec(align(4))
+#endif
+#elif defined(__GNUC__)
+#define PTR_ALIGNED __attribute__((aligned(sizeof(void *))))
+#else
+#define PTR_ALIGNED
+#endif
+
 /* Inside the libusbx code, mark all public functions as follows:
  *   return_type API_EXPORTED function_name(params) { ... }
  * But if the function returns a pointer, mark it as follows:
@@ -308,7 +322,7 @@ struct libusb_device {
 	struct libusb_device_descriptor device_descriptor;
 	int attached;
 
-	unsigned char os_priv
+	PTR_ALIGNED unsigned char os_priv
 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
 	[] /* valid C99 code */
 #else
@@ -325,7 +339,7 @@ struct libusb_device_handle {
 	struct list_head list;
 	struct libusb_device *dev;
 	int auto_detach_kernel_driver;
-	unsigned char os_priv
+	PTR_ALIGNED unsigned char os_priv
 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
 	[] /* valid C99 code */
 #else