Dropbox Lenovo ID Integration Flaw Exposes Thousands of Accounts Without Passwords
A flaw in the federated authentication process between Dropbox and Lenovo ID allowed attackers to compromise approximately 5,000 accounts between August 4 and August 21, 2026. Attackers registered a Lenovo ID using the email address tied to an existing Dropbox account due to missing email verification checks. They then logged in via the Lenovo ID option, and Dropbox automatically associated the identity with the existing account without requiring the original Dropbox password. Only accounts linked to the Lenovo ID integration and lacking two-factor authentication were affected. In fewer than one-third of the compromised accounts, attackers viewed or downloaded stored files. Dropbox responded by terminating all Lenovo ID sessions, removing existing associations, and updating the login flow to require the Dropbox password. Lenovo described the issue as stemming from a legacy integration and stated that its own customers were not directly impacted.
BoletimSecSep 3, 2026Translated from Portuguese