Instagram has denied it has been victim to a data breach after many users received emails prompting them to reset their password.

The firm said it had resolved a problem which allowed "an external party" to get the social media platform to send out legitimate password reset requests to users.

Instagram said there had been no breach of its systems, and told users their accounts were secure.

But some experts have questioned the statement, with cyber security firm Malwarebytes claiming the password reset emails had in fact been sent as a result of a hack.

"Cybercriminals stole the sensitive information of 17.5 million Instagram accounts, including usernames, physical addresses, phone numbers, email addresses, and more," it claimed in a post on X, along with a screenshot of a password reset email from Instagram.

No further details were given by the company, but the post has been viewed more than 2.3 million times.

Malwarebytes told the BBC it believed the password reset emails were a direct result of an ongoing sale of private data on a hacker forum, where a criminal has claimed to have the personal details of 17.5 million Instagram users.

The advert claims the data comes from a "leak" in 2024.

But some security researchers think it is actually an old database that was gathered from data which could be publicly viewed - such as names and locations - in 2022.

'No breach'

The password reset emails coupled with the Malwarebytes warning has prompted confusion for thousands of people on social media.

And Instagram's explanation also posed questions.

"We fixed an issue that let an external party request password reset emails for some people," the company said.

"There was no breach of our systems."

But Instagram did not respond to the BBC's questions about who the external party was which could send out legitimate password reset requests on behalf of the firm.

The emails caused concern for some users on social media, who feared it was a scam or phishing attempt designed to glean more of their details.

But the links in the email do not appear to be malicious, and the password reset process a user is guided through appeared to be legitimate.

However the advice, as ever, is to go straight to the website or app to make changes to passwords and add extra protection.