MSRC-CVE-2026-48579 — Microsoft Exchange Online Information Disclosure Vulnerability

Summary

Impact: Information Disclosure. Microsoft rating: Critical. Not known to be exploited. Customer action: Not required.

Details

Why are there no links to an update or instructions with steps that must be taken to protect from this vulnerability?
This vulnerability has already been fully mitigated by Microsoft. There is no action for users of this service to take. The purpose of this CVE is to provide further transparency.
Please see Toward greater transparency: Unveiling Cloud Service CVEs for more information.

Vulnerabilities 1

Critical 9.1

CVE-2026-48579

Microsoft Exchange Online Information Disclosure Vulnerability

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

Microsoft Microsoft Exchange Online

Jun 4, 2026

Revision history

2026-06-04 #1
Information published.

References

CVE-2026-48579 Microsoft Exchange Online Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-48579
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss