---
id: CVE-2026-48579
title: Microsoft Exchange Online Information Disclosure Vulnerability
summary: >-
  Improper authorization in Microsoft Exchange Online allows an unauthorized
  attacker to disclose information over a network.
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C'
cvssSource: cna
cwe:
  - CWE-285
vendor: Microsoft
product: Microsoft Exchange Online
affected:
  - exchange_online -
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-06-05T20:05:31.163433Z'
published: '2026-06-04'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T13:45:18.362Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-48579'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-48579'
    label: Microsoft Exchange Online Information Disclosure Vulnerability
tags:
  - cve.org
epss: 0.00999
epssPercentile: 0.61193
ingestedAt: '2026-09-24T14:44:21.357Z'
---

## Overview

Improper authorization in Microsoft Exchange Online allows an unauthorized attacker to disclose information over a network.

## Affected

- `exchange_online -`

## Remediation

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