---
id: CVE-2026-45503
title: >-
  Improper authorization in Microsoft Exchange Server allows an authorized
  attacker to disclose information over a network.
summary: >-
  Improper authorization in Microsoft Exchange Server allows an authorized
  attacker to disclose information over a network.
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-285
  - CWE-918
vendor: microsoft
product: exchange_server
affected:
  - exchange_server = 2016
  - exchange_server = 2019
  - exchange_server_subscription_edition < 15.02.2562.043
patched:
  - exchange_server_subscription_edition 15.02.2562.043
published: '2026-06-09'
updated: '2026-07-28'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45503'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45503'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
epss: 0.00445
epssPercentile: 0.38124
ingestedAt: '2026-07-28T23:40:23.593Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-06-10T13:41:09.056090Z'
---

## Overview

Improper authorization in Microsoft Exchange Server allows an authorized attacker to disclose information over a network.

## Affected

- `exchange_server = 2016`
- `exchange_server = 2019`
- `exchange_server_subscription_edition < 15.02.2562.043`

## Remediation

Upgrade past the affected range:

- `exchange_server_subscription_edition 15.02.2562.043`