---
id: CVE-2026-69375
title: >-
  Authorization bypass through user-controlled key in Microsoft Exchange Server
  allows an authorized attacker to perform tampering over a network.
summary: >-
  Authorization bypass through user-controlled key in Microsoft Exchange Server
  allows an authorized attacker to perform tampering over a network.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-639
vendor: Microsoft
product: Microsoft Exchange Server 2016 Cumulative Update 23
affected:
  - exchange_server_2016_cumulative_update_23 >= 15.01.0.0 < 15.01.2507.073
  - exchange_server_2019_cumulative_update_14 >= 15.02.0.0 < 15.02.1544.046
  - exchange_server_2019_cumulative_update_15 >= 15.02.0.0 < 15.02.1748.051
  - exchange_server_subscription_edition_rtm >= 15.02.0.0 < 15.02.2562.049
published: '2026-09-08'
updated: '2026-09-11'
sourceUpdated: '2026-09-11T15:17:02.730'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-69375'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69375'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-11T14:51:05.458653Z'
epss: 0.00591
epssPercentile: 0.4695
ingestedAt: '2026-09-08T19:08:49.610Z'
---

## Overview

Authorization bypass through user-controlled key in Microsoft Exchange Server allows an authorized attacker to perform tampering over a network.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.