CVE-2026-45502: Microsoft Exchange Server Information Disclosure Vulnerability

Overview

Severity
Medium (CVSS 5)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N/E:U/RL:O/RC:C
Category
Information Disclosure
Exploit Status
Not Exploited
Exploitation Likelihood
Unlikely
Patch Tuesday
2026-Jun
Released
2026-06-09

Description

Server-side request forgery (ssrf) in Microsoft Exchange Server allows an authorized attacker to disclose information over a network.

FAQ

According to the CVSS metrics, successful exploitation of this vulnerability could lead to some loss of confidentiality (C:L),but lead to no loss of availability (A:N) and integrity (I:N)? What does that mean for this vulnerability? An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality) but not all resources within the impacted component may be divulged to the attacker. The attacker cannot make changes to disclosed information (Integrity) or limit access to the resource (Availability). What type of information could be disclosed by this vulnerability? If successfully exploited, this vulnerability could allow an authenticated user to learn information about internal or external network services that the Exchange server can reach, such as whether a service exists and how it responds. In some cases, error details returned by the server may reveal network addresses, connection status, or limited response data from those services. According to the CVSS metric, a successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability? In this case, the Exchange server could be used to interact with other internal systems or services that are outside the normal security boundary of Exchange, potentially exposing information about those separate systems.

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

<a href="https://smlijun.github.io/">DongJun Kim (smlijun)</a> with UIUC, Hwiwon Lee (hwiwonl) with UIUC, Jongseong Kim (nevul37) with UIUC, Younggi Park (grill66) with UIUC, <a href="https://www.linkedin.com/in/talha--gunay/">TALHA G&#220;NAY</a>

Revision History

  • 2026-06-09: Information published.