CVE-2026-77910

Microsoft Exchange Server Elevation of Privilege Vulnerability

State: Published
Severity: 8.8 High
Published: Oct 13, 2026
Updated: Oct 31, 2026
Reserved: Aug 21, 2026

Description

Incorrect authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

Scores

CVSS	Score	Vector	Source
3.1	8.8 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
Microsoft Exchange Server 2016 Cumulative Update 23Microsoft	15.01.0.0 to before 15.01.2507.077Affected
Microsoft Exchange Server 2019 Cumulative Update 14Microsoft	15.02.0.0 to before 15.02.1544.050Affected
Microsoft Exchange Server 2019 Cumulative Update 15Microsoft	15.02.0.0 to before 15.02.1748.055Affected
Microsoft Exchange Server Subscription Edition RTMMicrosoft	15.02.0.0 to before 15.02.2562.056Affected

References

Microsoft Exchange Server Elevation of Privilege Vulnerabilityvendor-advisorypatch

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