diff --git a/Lib/test/test_winreg.py b/Lib/test/test_winreg.py
--- a/Lib/test/test_winreg.py
+++ b/Lib/test/test_winreg.py
@@ -329,6 +329,14 @@
         finally:
             DeleteKey(HKEY_CURRENT_USER, test_key_name)
 
+    def test_setvalueex_with_memoryview(self):
+        try:
+            with CreateKey(HKEY_CURRENT_USER, test_key_name) as ck:
+                self.assertNotEqual(ck.handle, 0)
+                SetValueEx(ck, "test_name", None, REG_BINARY, memoryview('val'))
+        finally:
+            DeleteKey(HKEY_CURRENT_USER, test_key_name)
+
     def test_queryvalueex_return_value(self):
         # Test for Issue #16759, return unsigned int from QueryValueEx.
         # Reg2Py, which gets called by QueryValueEx, was returning a value
diff --git a/PC/_winreg.c b/PC/_winreg.c
--- a/PC/_winreg.c
+++ b/PC/_winreg.c
@@ -888,7 +888,7 @@
             else {
                 void *src_buf;
                 PyBufferProcs *pb = value->ob_type->tp_as_buffer;
-                if (pb==NULL) {
+                if (pb == NULL || pb->bf_getreadbuffer == NULL) {
                     PyErr_Format(PyExc_TypeError,
                         "Objects of type '%s' can not "
                         "be used as binary registry values",
@@ -896,9 +896,11 @@
                     return FALSE;
                 }
                 *retDataSize = (*pb->bf_getreadbuffer)(value, 0, &src_buf);
-                *retDataBuf = (BYTE *)PyMem_NEW(char,
-                                                *retDataSize);
-                if (*retDataBuf==NULL){
+                if (*retDataSize < 0) {
+                    return FALSE;
+                }
+                *retDataBuf = (BYTE *)PyMem_NEW(char, *retDataSize);
+                if (*retDataBuf == NULL){
                     PyErr_NoMemory();
                     return FALSE;
                 }