diff --git a/drivers/filesystems/fastfat/dir.c b/drivers/filesystems/fastfat/dir.c
index 18c6dcc2ca..6c7d660c53 100644
--- a/drivers/filesystems/fastfat/dir.c
+++ b/drivers/filesystems/fastfat/dir.c
@@ -356,6 +356,9 @@ VfatGetFileBothInformation(
     NTSTATUS Status;
     ULONG BytesToCopy = 0;
 
+    if ((sizeof(FILE_BOTH_DIR_INFORMATION) + DirContext->LongNameU.Length) > BufferLength)
+        return STATUS_BUFFER_OVERFLOW;
+        
     *Written = 0;
     Status = STATUS_BUFFER_OVERFLOW;