CVE-2026-45500: Microsoft Exchange Server Spoofing Vulnerability

Overview

Severity
Medium (CVSS 6.1)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C
Category
Spoofing
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2026-Jun
Released
2026-06-09

Description

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

FAQ

According to the CVSS metrics, successful exploitation of this vulnerability could lead to some loss of confidentiality (C:L), and integrity (I:L) but lead to no loss of availability (A:N). What is the impact of this vulnerability? An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality), make changes to disclosed information (Integrity), but cannot limit access to the resource (Availability). According to the CVSS metric, a successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability? An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities. According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? User interaction in the Exchange Control Panel (ECP) is required to exploit this vulnerability.

Affected Products (4)

ESU

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

Server Software

  • Microsoft Exchange Server Subscription Edition RTM

Security Updates (1)

Acknowledgments

P1hcn, <a href="https://smlijun.github.io/">DongJun Kim</a> with UIUC, 41ae55e9310ff27fa6f26af4727e5590

Revision History

  • 2026-06-09: Information published.