CVE-2026-87692
Microsoft Exchange Server Elevation of Privilege Vulnerability
Microsoft Microsoft Exchange Server 2016 Cumulative Update 23Applications & CMS
CVSS
7.8HighExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)1.59%Chance of exploitation activity in the next 30 days, higher than 75% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
- 15.01.2507.077Microsoft Exchange Server 2016 Cumulative Update 23CVE List
- 15.02.1544.050Microsoft Exchange Server 2019 Cumulative Update 14CVE List
- 15.02.2562.056Microsoft Exchange Server Subscription Edition RTMCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
Vendor and government advisories 1
Vendors that say their products are affected, and agencies that issued alerts. Check each for the fixed release of the product you run.
Reports 1
1 outlet mention it. Reports are not confirmation; each links to its source.
Description
Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.
Text from CVE List
Affected versions 3
- Microsoft Exchange Server 2016 Cumulative Update 23affected: 15.01.0.0 before 15.01.2507.077CVE List
- Microsoft Exchange Server 2019 Cumulative Update 14affected: 15.02.0.0 before 15.02.1544.050CVE List
- Microsoft Exchange Server Subscription Edition RTMaffected: 15.02.0.0 before 15.02.2562.056CVE List