14 July 2026 1 min read

The Hidden Risk of Microsoft 365 Copilot: Data Oversharing

Microsoft 365 Copilot does not grant new access to anyone. That is exactly why it can be such a problem.

Copilot Works Within Existing Permissions, That Is the Risk

Microsoft 365 Copilot only surfaces content a user already has permission to see. It does not bypass security or create new access. The problem is that most business SharePoint and OneDrive environments have years of permission sprawl sitting quietly in the background, broad sharing links, groups given access for a project that finished long ago, folders shared with everyone in the company because it was easier than setting up proper groups at the time.

Before Copilot, that sprawl was largely harmless in practice because finding any specific file buried in it required knowing it existed and searching for it manually. Copilot changes that completely. Ask it a question and it will search across everything the user can technically access and summarise the answer instantly, including files nobody expected anyone to actually find.

What This Looks Like in Practice

A common example is an employee asking Copilot a general question about a project or a client, and receiving a summary that includes details from a spreadsheet they technically had view access to through an old shared link, but had no reason to know existed and were never meant to see in that context. Salary information, board documents, HR records, and draft contracts are the kinds of files that most commonly turn up this way, not because anyone did anything wrong, but because access was never properly cleaned up.

Getting Ready Before You Turn Copilot On

The fix is not to avoid Copilot, it is to properly prepare for it. That means auditing SharePoint and OneDrive permissions before rollout, removing access that is no longer needed, replacing broad everyone style sharing with proper groups, and applying sensitivity labels and data loss prevention policies to anything genuinely sensitive. Businesses that do this work upfront get the full benefit of Copilot without the surprises. Businesses that skip it usually find out about the gaps from an uncomfortable conversation after someone stumbles across something they should never have seen.

Where This Fits With Your Wider IT Strategy

This is exactly the kind of gap our AI Readiness service is built to close, reviewing your data governance and access controls before you roll Copilot out more broadly, not after. It also connects directly to our Identity and Access Management service, since permission cleanup is fundamentally an access control problem. If Copilot is already active in your business, or you are planning a rollout, it is worth checking what it can actually find before someone else does.

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