diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c
index 4882a812ea867..e11d4a1e63d73 100644
--- a/fs/smb/server/connection.c
+++ b/fs/smb/server/connection.c
@@ -294,6 +294,9 @@ bool ksmbd_conn_alive(struct ksmbd_conn *conn)
 	return true;
 }
 
+#define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr))
+#define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4)
+
 /**
  * ksmbd_conn_handler_loop() - session thread to listen on new smb requests
  * @p:		connection instance
@@ -350,6 +353,9 @@ int ksmbd_conn_handler_loop(void *p)
 		if (pdu_size > MAX_STREAM_PROT_LEN)
 			break;
 
+		if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE)
+			break;
+
 		/* 4 for rfc1002 length field */
 		/* 1 for implied bcc[0] */
 		size = pdu_size + 4 + 1;
@@ -377,6 +383,12 @@ int ksmbd_conn_handler_loop(void *p)
 			continue;
 		}
 
+		if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId ==
+		    SMB2_PROTO_NUMBER) {
+			if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE)
+				break;
+		}
+
 		if (!default_conn_ops.process_fn) {
 			pr_err("No connection request callback\n");
 			break;