Conservative MPs including Boris Johnson have had their phone numbers and other personal details revealed by the party’s conference app.
A Guardian columnist highlighted the security breach on Twitter, where she said she was able to access the personal details of Mr Johnson.
The BBC has also been able to access private information of attendees, but the problem has since been rectified.
The Conservative Party has been approached for comment.
BBC political correspondent Chris Mason said the technical glitch was “deeply, deeply embarrassing” for the party.
The Guardian’s Dawn Foster, who is attending the conference, tweeted about the security breach and said she had been able to access the former foreign secretary’s personal details, including his mobile phone number.
She shared a redacted picture of Mr Johnson’s profile, which did not reveal his phone number.
It appears that people could access an MP’s personal details by entering their email address, without a password, when pressing the attendee’s button in the app.
This button has since been removed.
The app was created by Australian firm Crown Comms.
It appears Twitter has taken down search terms to do with the app as it reveals the personal details of high-profile politicians.
The Press Association said the details of Environment Secretary Michael Gove had also been shared online.