CVE-2025-53786

Published Aug 6, 2025

Last updated 2 months ago

Microsoft Exchange Server

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-53786 is a vulnerability in Microsoft Exchange Server hybrid deployments. It allows an attacker with administrative access to an on-premises Exchange server to escalate privileges within the connected cloud environment. This can be achieved without leaving easily detectable traces. The vulnerability stems from the shared service principal used between on-premises Exchange servers and Exchange Online for authentication. By exploiting this, attackers can modify user passwords, convert cloud users to hybrid users, and impersonate hybrid users, gaining unchecked access for up to 24 hours. Microsoft recommends installing the April 2025 (or later) Hot Fix and implementing the changes in your Exchange Server and hybrid environment.

Description: On April 18th 2025, Microsoft announced Exchange Server Security Changes for Hybrid Deployments and accompanying non-security Hot Fix. Microsoft made these changes in the general interest of improving the security of hybrid Exchange deployments. Following further investigation, Microsoft identified specific security implications tied to the guidance and configuration steps outlined in the April announcement. Microsoft is issuing CVE-2025-53786 to document a vulnerability that is addressed by taking the steps documented with the April 18th announcement. Microsoft strongly recommends reading the information, installing the April 2025 (or later) Hot Fix and implementing the changes in your Exchange Server and hybrid environment.
Source: secure@microsoft.com
NVD status: Awaiting Analysis

Risk scores

CVSS 3.1

Type: Primary
Base score: 8
Impact score: 6
Exploitability score: 1.3
Vector string: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
Severity: HIGH

Weaknesses

secure@microsoft.com: CWE-287

Hype score: Not currently trending

References