CVE-2026-62913: Microsoft Exchange Server Remote Code Execution Vulnerability

Overview

Severity

High (CVSS 8.8)

CVSS Vector

CVSS:3.1/AV:N/AC:L/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

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Aug

Released

2026-08-11

Last Updated

2026-08-13

EPSS Score

0.91% (percentile: 58.4%)

Description

Heap-based buffer overflow in Microsoft Exchange Server allows an authorized attacker to execute code over a network.

FAQ

How could an attacker exploit this vulnerability? An authenticated attacker could exploit this vulnerability by sending a specially crafted request to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system.

Affected Products (4)

ESU

• Microsoft Exchange Server 2016 Cumulative Update 23
• Microsoft Exchange Server 2019 Cumulative Update 15
• Microsoft Exchange Server 2019 Cumulative Update 14

Server Software

• Microsoft Exchange Server Subscription Edition RTM

Security Updates (1)

• 5121573

Acknowledgments

Van1sher, <a href="https://x.com/xamroot">Max Toor</a> with Microsoft

Revision History

• 2026-08-11: Information published.
• 2026-08-12: Updated an acknowledgement. This is an informational change only.
• 2026-08-13: Added acknowledgements. This is an informational change only.