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TI-2021-13500 Aliases CVE-2021-34470GHSA-hxhm-28wc-v3qm

Microsoft Exchange Server Elevation of Privilege Vulnerability

Priority HIGH 70Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Privilege escalation
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.

Summary

Microsoft Exchange Server Elevation of Privilege Vulnerability

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.04379 91st percentileScored 2026-11-07
Fix Fixed Microsoft: 3 updates

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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 2013 Cumulative Update 2315.00.0 to before 15.00.1497.02315.00.1497.023Patch availableCNA
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 2115.01.0 to before 15.01.2308.00815.01.2308.008Patch availableCNA
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 1015.02.0 to before 15.02.0922.00715.02.0922.007Patch availableCNA
  • Microsoft Exchange Server 2013 Cumulative Update 23 VendorMicrosoft Affected 15.00.0 to before 15.00.1497.023 Fixed in 15.00.1497.023 Patch available CNA
  • Microsoft Exchange Server 2016 Cumulative Update 21 VendorMicrosoft Affected 15.01.0 to before 15.01.2308.008 Fixed in 15.01.2308.008 Patch available CNA
  • Microsoft Exchange Server 2019 Cumulative Update 10 VendorMicrosoft Affected 15.02.0 to before 15.02.0922.007 Fixed in 15.02.0922.007 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*2013 cumulative_update_23VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_21:*:*:*:*:*:*2016 cumulative_update_21VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_10:*:*:*:*:*:*2019 cumulative_update_10VulnerableMicrosoft
  • cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:* Versions 2013 cumulative_update_23 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_21:*:*:*:*:*:* Versions 2016 cumulative_update_21 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_10:*:*:*:*:*:* Versions 2019 cumulative_update_10 Vulnerable ·Microsoft

Remediation

Microsoft 3 updates

  • KB5004778
    Security Update
    • Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.023
  • KB5003612
    Security Update
    • Microsoft Exchange Server 2019 Cumulative Update 10 15.02.0922.007
  • KB5003611
    Security Update
    • Microsoft Exchange Server 2016 Cumulative Update 21 15.01.2308.008

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Elevation of Privilege
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Less Likely

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-34470
  2. 2026-10-03 Alias added: GHSA-hxhm-28wc-v3qm

References

Patch 2

Advisory 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