Australian airline Qantas said Sunday that data from 5.7 million customers stolen in a major cyberattack this year had been shared online, part of a leak affecting dozens of firms.

Disney, Google, IKEA, Toyota, McDonald's and fellow airlines Air France and KLM are also reported to have had data stolen in a cyberattack targeting software firm Salesforce, with the information now being held to ransom.

Salesforce said this month it was "aware of recent extortion attempts by threat actors."