The security breach exposed the agent's support ticket queue, which contained user email addresses, messages exchanged with Discord support, and any attachments sent as part of the tickets.
Discord says it immediately addressed the breached support account by disabling it once the incident was discovered.
"Due to the nature of the incident, it is possible that your email address, the contents of customer service messages and any attachments sent between you and Discord may have been exposed to a third party," Discord said in letters sent to affected users.
"As soon as Discord was made aware of the issue, we deactivated the compromised account and completed malware checks on the affected machine."
