diff --git a/reactos/dll/win32/advapi32/sec/ac.c b/reactos/dll/win32/advapi32/sec/ac.c
index f9e64658419..e7c11e09d95 100644
--- a/reactos/dll/win32/advapi32/sec/ac.c
+++ b/reactos/dll/win32/advapi32/sec/ac.c
@@ -581,6 +581,11 @@ SetEntriesInAclW(ULONG cCountOfExplicitEntries,
 {
     DWORD ErrorCode;
 
+    if (!NewAcl)
+    {
+        return ERROR_INVALID_PARAMETER;
+    }
+
     ErrorCode = CheckNtMartaPresent();
     if (ErrorCode == ERROR_SUCCESS)
     {