diff --git a/reactos/dll/win32/advapi32/reg/reg.c b/reactos/dll/win32/advapi32/reg/reg.c
index 919e78b7013..49230b9cd1a 100644
--- a/reactos/dll/win32/advapi32/reg/reg.c
+++ b/reactos/dll/win32/advapi32/reg/reg.c
@@ -3272,6 +3272,9 @@ RegOpenKeyA(HKEY hKey,
     TRACE("RegOpenKeyA hKey 0x%x lpSubKey %s phkResult %p\n",
           hKey, lpSubKey, phkResult);
 
+    if (!phkResult)
+        return ERROR_INVALID_PARAMETER;
+
     if (!hKey && lpSubKey && phkResult)
     {
         return ERROR_INVALID_HANDLE;
@@ -3308,6 +3311,9 @@ RegOpenKeyW(HKEY hKey,
     TRACE("RegOpenKeyW hKey 0x%x lpSubKey %S phkResult %p\n",
           hKey, lpSubKey, phkResult);
 
+    if (!phkResult)
+        return ERROR_INVALID_PARAMETER;
+
     if (!hKey && lpSubKey && phkResult)
     {
         return ERROR_INVALID_HANDLE;