MSRC-CVE-2026-62911 — Microsoft Exchange Server Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited the vulnerability?
The attacker would be able to take over the mailboxes of all Exchange users, attackers can send emails, read emails, download attachments.

Security updates
15.01.2507.072 — https://support.microsoft.com/help/5121576
15.02.2562.046 — https://support.microsoft.com/help/5121573
15.02.1748.049 — https://support.microsoft.com/help/5121574
15.02.1544.044 — https://support.microsoft.com/help/5121575

Vulnerabilities 1

High 8.0

CVE-2026-62911 Public exploit

Microsoft Exchange Server Elevation of Privilege Vulnerability

Authentication bypass by capture-replay in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 Microsoft Exchange Server Subscription Edition RTM Microsoft Exchange Server 2019 Cumulative Update 14

Aug 11, 2026

Revision history

2026-08-11 #1
Information published.

References

CVE-2026-62911 Microsoft Exchange Server Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62911
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