CVE-2026-62911

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.

Affected

Microsoft · Microsoft Exchange Server 2016 Cumulative Update 23 · Microsoft Exchange Server 2019 Cumulative Update 14 · Microsoft Exchange Server 2019 Cumulative Update 15 · Microsoft Exchange Server Subscription Edition RTM

CVSS v3.1 MICROSOFT

8.0 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

EPSS

0.69% chance of exploitation in the next 30 days, 52nd percentile

Published

2026-08-11

Updated

2026-10-08

Proof-of-concept exploits (1)

• hypnguyen1209/CVE-2026-62911187★ · 2026-08-22

Security advisories

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62911

References

• CVE Record
• NVD entry

Related

• CVE-2026-55040
• CVE-2026-63520