Microsoft admits Office bug exposed users’ confidential emails to Copilot

• Copilot Chat was reading sent and draft emails, but the Inbox folder appears to have been protected
• The bug (CW1226324) was identified in January, a fix followed in February
• Although the fix is ​​rolling out, this is still a persistent issue.

Microsoft has confirmed that a bug in M365 Copilot Chat allowed the AI ​​chatbot to summarize confidential emails without users’ permission, bypassing data loss prevention (DLP) policies and sensitivity/privacy labels designed to prevent Copilot from accessing emails in the first place.

Although inboxes were not affected, Copilot Chat had access to the Sent and Drafts folders, and likely entire email threads within those, which also include incoming emails.

Tracked internally as CW1226324, the bug was first identified on January 21, 2026, but the company has already deployed a patch and continues to monitor the situation.

M365 Copilot Chat read your sensitive emails

“Email messages from users with a confidential label are being handled incorrectly by Microsoft 365 Copilot chat,” the advisory states.

Microsoft says an error code caused the problem, which allowed these labeled emails to be retrieved: “A code issue allows items in Sent Items and Draft folders to be retrieved by Copilot even if sensitive labels are set.”

The company began rolling out a patch in early February that it continues to monitor, but it appears to be an ongoing issue that has not yet been fully resolved.

It is also believed that Microsoft is contacting affected users as the patch rolls out and continues to verify the fix.

The timing of Microsoft’s mistake is also very unfortunate, with the European Parliament recently banning all AI tools on workers’ devices on the grounds that many systems were sharing data with the cloud, even though they could theoretically process it locally.

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With several years of freelance experience in technology and automotive circles, Craig’s specific interests lie in technologies designed to improve our lives, including AI and ML, productivity aids, and smart fitness. He is also passionate about automobiles and the decarbonization of personal transportation. As an avid bargain hunter, you can be sure that any deal Craig finds is great value for money!