A security breach at a big data company exposed data from about 60 million people to hackers, the cybersecurity firm CloudFlare said.
The breach at Kaspersky Lab, one of the largest in the world, also affected some 100 million accounts, the company said.
Kasperski was a subsidiary of Moscow-based Kaspersnogo.
The breach occurred in April, and the company patched the bug on Monday, the Kaspersko website said.
CloudFlare has been advising users to change their passwords.
The company said it also recommends users change their email addresses and change their phone numbers and email addresses.
The vulnerability could be exploited by hackers to get access to sensitive data, CloudFlares said.
It is unclear how many people were affected.
Cloudflare’s statement said Kaspersk had not yet fixed the issue.