CVE-2026-47645: Microsoft 365 Copilot's Business Chat Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 8.8)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Elevation of Privilege

Exploit Status

Not Exploited

Patch Tuesday

2026-Jun

Released

2026-06-18

Description

Url redirection to untrusted site ('open redirect') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to elevate privileges over a network.

FAQ

Why are there no links to an update or instructions with steps that must be taken to protect from this vulnerability? This vulnerability has already been fully mitigated by Microsoft. There is no action for users of this service to take. The purpose of this CVE is to provide further transparency. Please see Toward greater transparency: Unveiling Cloud Service CVEs for more information.

Affected Products (1)

Apps

• Microsoft 365 Copilot

Acknowledgments

Yogeesh Seralathan with Microsoft

Revision History

• 2026-06-18: Information published.