A hacker broke into about 5,000 accounts at cloud storage provider Dropbox by exploiting a login authentication flaw involving PC maker Lenovo.
Several users reported receiving an email from Dropbox on Monday, warning about the hack. “We are writing to let you know that we’ve observed unauthorized access to your Dropbox account between August 4 and August 21, 2026,” the company wrote.
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A hacker gained access by abusing Lenovo ID, the company’s login and account system. A Lenovo ID can be used to sign up and access Dropbox, but it looks like that system can create a path to hijack an existing Dropbox account if the user’s email address is known.
In the email, Dropbox explained: “While you may not have an existing Lenovo ID, our investigation determined that an issue with Lenovo’s email verification process allowed an unauthorized party to register a Lenovo ID using your email address and then use that Lenovo ID to log into the Dropbox account associated with that email address.”
So, rather than viewing the two logins as separate, Dropbox/Lenovo treated them as one since both shared the same email address. “Damn, big security f***** by Dropbox,” wrote one user on the Hacker News forum as the hijacking came to light. “You should never allow linking of an existing account with a new login method without first confirming that the user is able to sign in with an existing method first!”
The breach is concerning since Dropbox is often used to store sensitive files and documents. However, the scale of the attack is relatively small. Bloomberg reports that the hacker compromised only about 5,000 accounts, none of which were protected by multi-factor authentication. Meanwhile, Lenovo has described the login issue as a “legacy integration” with Dropbox that both companies have worked to address.
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In some cases, Dropbox also appears to tell users, “Our logs show no evidence that your files were viewed or downloaded,” adding, “To secure your account, we promptly expired all sessions logged in through Lenovo IDs. We also severed any link between Lenovo and your Dropbox account, and no one can access your Dropbox account via a Lenovo ID without first entering your Dropbox password.”
Dropbox didn’t immediately respond to a request for comment.
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I’ve been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I’m currently based in San Francisco, but previously spent over five years in China, covering the country’s technology sector.
Since 2020, I’ve covered the launch and explosive growth of SpaceX’s Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I’ve combed through FCC filings for the latest news and driven to remote corners of California to test Starlink’s cellular service.
I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.
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