OpenAI disclosed details of a ChatGPT outage that occurred on March 20, 2023, affecting user access and exposing a data privacy issue [source]. The incident began when the service became unavailable to users, prompting investigation by OpenAI's engineering team.

During the outage window, a bug in an open-source library caused some users to see titles from other users' chat histories in their sidebar. OpenAI confirmed that approximately 1.2% of ChatGPT Plus subscribers who were active during a specific nine-hour window may have had their conversation titles visible to other users. The company stated that the same bug may have allowed some users to see another active user's first and last name, email address, payment address, and partial credit card information.

The vulnerability was traced to a Redis client library issue that caused cache data to be returned to incorrect users under specific conditions. OpenAI took ChatGPT offline to patch the library and implement additional safeguards. The company reported that it has since added redundant checks to prevent similar cache corruption issues.

OpenAI stated it is directly notifying affected users and has reported the incident to relevant data protection authorities. The company emphasized that no passwords were exposed and that full credit card numbers were not stored in the affected cache layer.

The disclosure comes four days after the initial outage, with OpenAI publishing a technical post-mortem explaining the root cause. The incident represents a significant service disruption combined with a data exposure event affecting paying subscribers during peak usage hours.