Authentication Bypass by Capture-replay in Microsoft Exchange Server - CVE-2026-62911
Published: August 12, 2026 / Updated: September 2, 2026
Vulnerability identifier: #VU141972
CSH Severity: Medium
CVSS v4: 8.4 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-62911
CWE-ID: CWE-294
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vulnerability details
The vulnerability allows a remote user to elevate privileges.
The vulnerability exists due to the server is susceptible to authentication bypass by capture-replay. A remote authenticated user can take over the mailboxes of all Exchange users.
Affected software
Microsoft Exchange Server
How to mitigate CVE-2026-62911
Install updates from vendor's website.
Microsoft Exchange Server - addressed in versions SE RTM Aug26SU 15.02.2562.046, 2016 CU23 Aug26SU 15.01.2507.072, 2019 CU14 Aug26SU 15.02.1544.044, 2019 CU15 Aug26SU 15.02.1748.049