Topic starter
04/06/2026 3:02 pm
TL;DR: A flaw in Microsoft’s OneDrive File Picker can let connected web apps access a user’s entire OneDrive instead of only selected files, affecting hundreds of apps and potentially millions of users, according to Oasis Security. The issue exposes how vague consent, broad OAuth scopes, and token handling can turn routine file sharing into enterprise data exposure.
Editorial analysis by NHI Mgmt Group, based on content published by Oasis Security: “OneDrive File Picker Flaw Provides ChatGPT and Other Web Apps Full Read Access to Users’ Entire OneDrive”.
Key questions
Q: What breaks when a file picker grants cloud access instead of true file-level permissions?
A: True least-privilege sharing breaks down because the app may receive access to far more content than the user intended.
Q: Why do broad delegated file permissions create more risk than a normal upload flow?
A: Because the permission often outlives the upload.
Q: What are the signs that a third-party file picker integration is mis-scoped?
A: Look for consent prompts that do not clearly state the scope, apps that request drive-wide access for single-file actions, browser-side token storage, and refresh tokens that extend access beyond the immediate upload session.
Practitioner guidance
- Review delegated app scopes Inventory connected apps and verify whether each granted scope matches the actual file-sharing task, especially where OneDrive access is broader than a selected upload item.
- Remove browser-side token persistence Eliminate session storage or local storage patterns that keep access tokens available in the browser longer than needed, and dispose of refresh tokens if they are not required.
- Rework consent wording and approval review Make consent prompts and admin review steps state the real access boundary in plain language so users and reviewers can see when a web app is receiving drive-wide read access.
Bottom line: The flaw is not just a bad upload experience. It is a delegated access problem that can turn a single user action into broad file exposure.
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04/06/2026 3:15 pm
Consent wording is not a usability detail when delegated file access is involved. This flaw shows that vague prompts can become an authorization failure, because users approve a workflow without understanding the true access boundary. In practice, file-sharing consent must be treated as part of the access model, not a wrapper around it. Practitioners should assume that unclear consent language creates governance debt, not just user confusion.
A question worth separating out:
Q: How should teams govern delegated access from web apps to cloud file stores?
A: Treat it as an identity governance problem, not just an application integration. Teams should verify scope precision, review which apps can reach user files, control token lifetime, and make revocation simple enough that access can be removed when the business need ends.
👉 Read our full editorial: OneDrive File Picker flaws expose broad app access to files