We took ChatGPT offline earlier this week due to a bug in an open-source library which allowed some users to see titles from another active user’s chat history. It’s also possible that the first message of a newly-created conversation was visible in someone else’s chat history if both users were active around the same time.

The bug is now patched. We were able to restore both the ChatGPT service and, later, its chat history feature, with the exception of a few hours of history. As promised, we’re publishing more technical details⁠ of this problem below.

Upon deeper investigation, we also discovered that the same bug may have caused the unintentional visibility of payment-related information of 1.2% of the ChatGPT Plus subscribers who were active during a specific nine-hour window. In the hours before we took ChatGPT offline on Monday, it was possible for some users to see another active user’s first and last name, email address, payment address, credit card type and the last four digits (only) of a credit card number, and credit card expiration date. Full credit card numbers were not exposed at any time. 

We believe the number of users whose data was actually revealed to someone else is extremely low. To access this information, a ChatGPT Plus subscriber would have needed to do one of the following:

• Open a subscription confirmation email sent on Monday, March 20, between 1 a.m. and 10 a.m. Pacific time. Due to the bug, some subscription confirmation emails generated during that window were sent to the wrong users. These emails contained the credit card type and last four digits of another user’s credit card number, but full credit card numbers did not appear. It’s possible that a small number of subscription confirmation emails might have been incorrectly addressed prior to March 20, although we have not confirmed any instances of this.
• In ChatGPT, click on “My account,” then “Manage my subscription” between 1 a.m. and 10 a.m. Pacific time on Monday, March 20. During this window, another active ChatGPT Plus user’s first and last name, email address, payment address, the credit card type and last four digits (only) of a credit card number, and credit card expiration date might have been visible. It’s possible that this also could have occurred prior to March 20, although we have not confirmed any instances of this.

We have reached out to notify affected users that their payment information may have been exposed. We are confident that there is no ongoing risk to users’ data. 

Everyone at OpenAI is committed to protecting our users’ privacy and keeping their data safe. It’s a responsibility we take incredibly seriously. Unfortunately, this week we fell short of that commitment, and of our users’ expectations. We apologize again to our users and to the entire ChatGPT community and will work diligently to rebuild trust.