(Pwn2Own) Microsoft Exchange Improper Authorization Privilege Escalation Vulnerability

August 11th, 2026
ZDI-26-538 ZDI-CAN-31480

CVE ID

CVE-2026-62911

CVSS Score

8.8 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors

Microsoft

Affected Products

Exchange

Vulnerability Details

This vulnerability allows remote attackers to escalate privileges on affected installations of Microsoft Exchange. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed.

The specific flaw exists within the handling of authorization requests. The issue results from improper session management. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of SYSTEM.

Additional Details

Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62911

Disclosure Timeline

  • 2026-05-21 - Vulnerability reported to vendor
  • 2026-08-11 - Coordinated public release of advisory
  • 2026-08-11 - Advisory Updated

Credit

Orange Tsai (@orange_8361) from DEVCORE Research Team

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