diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index f2483548cde92d692f748d6a9c7da0cbf98274a3..0dc0c78f1fdb2db40fd9dedb4b179999ac98fc60 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -407,7 +407,7 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v)
 		bytes = ~0ull;
 	else if (size & 0x8000)
 		bytes = (u64)(size & 0x7fff) << 10;
-	else if (size != 0x7fff)
+	else if (size != 0x7fff || dm->length < 0x20)
 		bytes = (u64)size << 20;
 	else
 		bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20;