Read the docs
TI-2026-72851 Aliases CVE-2026-87692GHSA-jjf3-cp8q-9qw7

Microsoft Exchange Server flaw allows local privilege escalation

Priority MEDIUM 40CWE-502Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-502.

Summary

Microsoft Exchange Server 2016 Cumulative Update 23 from 15.01.0.0 before 15.01.2507.077, Exchange Server 2019 Cumulative Update 14 from 15.02.0.0 before 15.02.1544.050, and Exchange Server Subscription Edition RTM from 15.02.0.0 before 15.02.2562.056 are affected. Deserialization of untrusted data (CWE-502) lets an authorized local attacker gain higher privileges. The attacker needs low privileges and no user interaction.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.02311 83rd percentileScored 2026-11-08
Fix Fixed Microsoft Exchange Server 2016 Cumulative Update 23 (Microsoft): 15.01.2507.077Microsoft Exchange Server 2019 Cumulative Update 14 (Microsoft): 15.02.1544.050+1 more product

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 2315.01.0.0 to before 15.01.2507.07715.01.2507.077Patch availableCNA
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 1415.02.0.0 to before 15.02.1544.05015.02.1544.050Patch availableCNA
MicrosoftMicrosoft Exchange Server Subscription Edition RTM15.02.0.0 to before 15.02.2562.05615.02.2562.056Patch availableCNA
  • Microsoft Exchange Server 2016 Cumulative Update 23 VendorMicrosoft Affected 15.01.0.0 to before 15.01.2507.077 Fixed in 15.01.2507.077 Patch available CNA
  • Microsoft Exchange Server 2019 Cumulative Update 14 VendorMicrosoft Affected 15.02.0.0 to before 15.02.1544.050 Fixed in 15.02.1544.050 Patch available CNA
  • Microsoft Exchange Server Subscription Edition RTM VendorMicrosoft Affected 15.02.0.0 to before 15.02.2562.056 Fixed in 15.02.2562.056 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_23:*:*:*:*:*:*2016 cumulative_update_23VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_14:*:*:*:*:*:*2019 cumulative_update_14VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server_subscription_edition:*:*:*:*:*:*:*:*before 15.02.2562.056VulnerableMicrosoft
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_23:*:*:*:*:*:* Versions 2016 cumulative_update_23 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_14:*:*:*:*:*:* Versions 2019 cumulative_update_14 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server_subscription_edition:*:*:*:*:*:*:*:* Versions before 15.02.2562.056 Vulnerable ·Microsoft

Remediation

Install the fixed versions: 15.01.2507.077 for Exchange Server 2016 Cumulative Update 23, 15.02.1544.050 for Exchange Server 2019 Cumulative Update 14, and 15.02.2562.056 for Exchange Server Subscription Edition RTM.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Microsoft Exchange Server 2016 Cumulative Update 23 (Microsoft) Fixed in 15.01.2507.077
  • Fix · CNA Microsoft Exchange Server 2019 Cumulative Update 14 (Microsoft) Fixed in 15.02.1544.050
  • Fix · CNA Microsoft Exchange Server Subscription Edition RTM (Microsoft) Fixed in 15.02.2562.056

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-87692
  2. 2026-10-13 Alias added: GHSA-jjf3-cp8q-9qw7
  3. 2026-10-31 Priority changed: LOW → MEDIUM

References

Patch 1

  • TI-2024-14170 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-19610 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-13547 Microsoft Exchange Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-13502 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2021-08465 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-07929 Microsoft Exchange Server Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
See all 258 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences