CVE-2026-96185: Microsoft Exchange Online Remote Code Execution Vulnerability

Overview

Severity

High (CVSS 7.5)

CVSS Vector

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

Category

Remote Code Execution

Exploit Status

Not Exploited

Patch Tuesday

2026-Oct

Released

2026-10-22

Description

Stack-based buffer overflow in Microsoft Exchange Online allows an authorized attacker to execute code 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)

Server Software

• Microsoft Exchange Online

Acknowledgments

<a href="https://smlijun.github.io/">DongJun Kim (smlijun)</a> with UIUC, <a href="https://hwiwonl.ee/">Hwiwon Lee (hwiwonl)</a> with UIUC, <a href="https://nevul37.github.io/">Jongseong Kim (nevul37)</a> with UIUC, Younggi Park (grill66) with UIUC

Revision History

• 2026-10-22: Information published.