The initial report about this flaw was made in June by researchers at the security start-up Senrio who noticed it in the firmware of the D-Link DCS-930L Network Cloud Camera. This camera can be controlled by a smartphone app.

According to them, a stack overflow exists in a service known as dcp that processes remote commands. The overflow can be exploited by transmitting specially crafted commands and then malicious code can be executed.

The Senrio team confirmed that the vulnerability existed in five cameras in the D-Link product range.

The dcp service is part and parcel of the agent that connects the device with the manufacturer's mydlink service.

Senrio told the PCWorld website that D-Link had investigated the issue and found that more than 120 models were affected, ranging from cameras, routers, and access points, to modems and storage devices.

Using the Shodan search engine, Senrio found more than 400,000 D-Link devices that are exposed to the Web.

Contacted for comment, a D-Link spokesman said the company's engineers had been working hard to patch the flaw since the report was first made.

"Since being given the full details on 17 June, we have been working to address the vulnerability in the network application interface, which occurs when malicious data is injected via the DCP protocol. We are testing the firmware to fix DCS-930L and expect to release it by the end of next week, 15 July."

He said firmware testing was now occurring on patches for other models and this would be built into new UID agents.

"As soon as there are further updates, we will make them available on our mydlink service for automatic upgrade or via our support website for manual download.

"To benefit from security updates, it is essential that customers regularly review all of the devices on their network to check that each device is running the latest firmware.

"We also recommend that customers use strong passwords, and that they change these passwords regularly. Advice on how to check and update firmware on D-Link devices can be found here."