Magento Marketplace users were informed this week that a vulnerability allowed an unauthorized third party to gain access to some account information. The breach was discovered on November 21 and the service was temporarily shut down to address the security issue. Names, email, MageID, billing and shipping address, and phone numbers were also exposed to the hacker. Passwords and card info is safe; more sensitive data like financial information related to payment cards remained unaffected. Magento says that while the problem is fixed, the recommendation for following security best practices to protect stores still stands.
Source: https://www.bleepingcomputer.com/news/security/adobe-magento-marketplace-exposed-user-info-in-data-breach/