Music-streaming service Spotify has become the latest high-profile technology company to be hit by a security breach.
The Swedish firm said no financial data had been accessed, and there was no “increased risk”.
A portion of its 40 million users will need to re-enter, but not change, their log-in credentials.
Furthermore, all users of its Android mobile app would be forced to upgrade “over the next few days”.
“We’ve become aware of some unauthorised access to our systems and internal company data,” chief technology officer Oskar Stål wrote on the firm’s website.
“Our evidence shows that only one Spotify user’s data has been accessed and this did not include any password, financial or payment information.
“We have contacted this one individual. Based on our findings, we are not aware of any increased risk to users as a result of this incident.”
While the breach was small in scale, Dwayne Melancon, chief technology officer at security firm Tripwire, said it could hint towards a troubling problem for the streaming firm.
“Had this been as simple as one user over-sharing their login credentials, it would not warrant an all-user notification,” he said, in an email.
“Given that Spotify claims that only one user’s data has been compromised, I suspect this was achieved via a re-usable, broadly applicable attack method perhaps affecting older versions of the Spotify app.
“My guess would be that someone demonstrated a proof-of-concept attack for the Spotify team and that constitutes the single known affected user.”
News of the breach comes a week after auction site eBay told all of its users to change their passwords.
Again, no financial data was believed to have been taken – but other personal data, such as home addresses, was accessed.