diff --git a/dlls/wininet/internet.c b/dlls/wininet/internet.c
index 53597944a99..e192592693a 100644
--- a/dlls/wininet/internet.c
+++ b/dlls/wininet/internet.c
@@ -2280,7 +2280,7 @@ BOOL WINAPI InternetReadFileExW(HINTERNET hFile, LPINTERNET_BUFFERSW lpBuffer,
 
     TRACE("(%p %p 0x%x 0x%lx)\n", hFile, lpBuffer, dwFlags, dwContext);
 
-    if (lpBuffer->dwStructSize != sizeof(*lpBuffer)) {
+    if (!lpBuffer || lpBuffer->dwStructSize != sizeof(*lpBuffer)) {
         SetLastError(ERROR_INVALID_PARAMETER);
         return FALSE;
     }
diff --git a/dlls/wininet/tests/http.c b/dlls/wininet/tests/http.c
index b4cad7d15ba..78cec504564 100644
--- a/dlls/wininet/tests/http.c
+++ b/dlls/wininet/tests/http.c
@@ -1067,6 +1067,11 @@ static void InternetReadFileExA_test(int flags)
     CLEAR_NOTIFIED(INTERNET_STATUS_CONNECTING_TO_SERVER);
     CLEAR_NOTIFIED(INTERNET_STATUS_CONNECTED_TO_SERVER);
 
+    rc = InternetReadFileExW(hor, NULL, 0, 0xdeadcafe);
+    ok(!rc && (GetLastError() == ERROR_INVALID_PARAMETER),
+        "InternetReadFileEx should have failed with ERROR_INVALID_PARAMETER instead of %s, %u\n",
+        rc ? "TRUE" : "FALSE", GetLastError());
+
     /* tests invalid dwStructSize */
     inetbuffers.dwStructSize = sizeof(inetbuffers)+1;
     inetbuffers.lpcszHeader = NULL;