Qantas says a technology issue is believed to be behind a problem with its app that allowed customers to see other people's flight information.
The airline said the issue was resolved in a 12.10pm update on May 1 and there was no indication of a cyber security incident.
"The issue was isolated to the Qantas app with some frequent flyers able to see the travel information of other customers, including name, upcoming flight details, points balance and status," the statement said.
"No further personal or financial information was shared and customers would not have been able to transfer or use the Qantas Points of other frequent flyers."
Qantas said it was not aware of any customers travelling with incorrect boarding passes.
It comes after travellers reported being automatically logged into random accounts, giving them access to flight details, boarding passes and the personal details of strangers.
In one instance a customer said they were able to access full booking details and had the ability to cancel someone's flight to Europe.
"PSA. Is anyone else's app glitching. I have access to 3 different peoples profiles when I opened it this morning. I don't know any of them," one person said on Facebook.
Replies flooded in from others experiencing the same issue with concerns it could result in a data breach.
"I am getting random people every time I refresh! Even their boarding passes," one person said.
"Same here. I was Sally now I am Caroline and I'm going to Singapore, not Brisbane. Serious data breach," another added.
In an earlier statement Qantas said it was 'urgently working' to fix the issue and apologised to affected customers.
