CVE-2025-59249: Microsoft Exchange Server Elevation of Privilege 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

Elevation of Privilege

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2025-Oct

Released

2025-10-14

EPSS Score

0.08% (percentile: 24.8%)

Description

Weak authentication in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

FAQ

What privileges could be gained by an attacker who successfully exploited the vulnerability? The attacker would be able to take over the mailboxes of all Exchange users, attackers can send emails, read emails, download attachments. How could an attacker exploit this vulnerability? An attacker would first have to compromise with a user account who is member of an admin group to run the required code.

Affected Products (4)

ESU

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

Server Software

• Microsoft Exchange Server Subscription Edition RTM

Security Updates (4)

• 5066369
• 5066368
• 5066367
• 5066366

Acknowledgments

Justin Hendricks

Revision History

• 2025-10-14: Information published.