Twitter on Friday disclosed that it fixed a bug in its Account Activity API (AAAPI) for app developers that may have mistakenly sent certain user data and content to the wrong developers who were not authorized to see this information.

The AAAPI, which enables developers build tools that help customers communicate via Twitter, contained the bug for over a year, from May 2017 through Sept. 10, 2018. Twitter claimed on its Help Center page that fewer than one percent of Twitter users were affected, and that it began contacting these individuals as well as impacted developers. (There were reportedly 335 million monthly active Twitter users worldwide in the first quarter of 2018.)

Affected interactions between users and apps leverage may have included direct messages and protected tweets, the social media platform acknowledged in an online announcement. "Similarly, if your business authorized a developer using the AAAPI to access your account, the bug may have impacted your activity data in error," Twitter wrote.

Twitter also said that its initial analysis reveals that the inadvertent sharing of account information with the wrong registered developer’s webhook URL was only possible under "a complex series of technical circumstances." A more detailed description of the problem on Twitter's Developer Blog explains that this involved two or developers both having:

  • API subscriptions configured for domains resolving to the same public IP
  • matching URL paths after the domain
  • subscription activity taking place in the same six-minute time period
  • activities originating from the same backend server in Twitter’s datacenter

"Our team has been working diligently with our most active enterprise data customers and partners who have access to this API to evaluate if they were impacted," Twitter said.