CVE-2025-53782: Microsoft Exchange Server Elevation of Privilege Vulnerability

Overview

Severity
High (CVSS 8.4)
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/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
Less Likely
Patch Tuesday
2025-Oct
Released
2025-10-14
EPSS Score
0.07% (percentile: 20.4%)

Description

Incorrect implementation of authentication algorithm in Microsoft Exchange Server allows an unauthorized attacker to elevate privileges locally.

FAQ

How could an attacker exploit this vulnerability? To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. Additionally, an attacker could convince a local user to open a malicious file. The attacker would have to convince the user to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file. 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, read emails, download attachments.

Affected Products (4)

ESU

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

Server Software

  • Microsoft Exchange Server Subscription Edition RTM

Security Updates (4)

Acknowledgments

<a href="https://github.com/zcgonvh">zcgonvh&#39;s cat Vanilla</a>

Revision History

  • 2025-10-14: Information published.