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TI-2021-08464 Aliases CVE-2021-26854GHSA-2xf7-r7hp-r5qc

Microsoft Exchange Server Remote Code Execution Vulnerability

Priority MEDIUM 53Published · Updated

Key facts

Attack vector
Network
Privileges required
High
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 · NVD. Fix status from CNA and Microsoft. Impact type from Microsoft.

Summary

Microsoft Exchange Server Remote Code Execution Vulnerability

Why it matters now

EPSS 0.24742 97th percentileScored 2026-11-07
Fix Fixed Microsoft: 1 update

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftMicrosoft Exchange Server 2013 Cumulative Update 2315.00.0 to before 15.00.1497.01215.00.1497.012Patch availableCNA
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1815.01.0 to before 15.01.2106.01315.01.2106.013Patch availableCNA
MicrosoftMicrosoft Exchange Server 2016 Cumulative Update 1915.01.0 to before 15.01.2176.00915.01.2176.009Patch availableCNA
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 715.02.0 to before 15.02.0721.01315.02.0721.013Patch availableCNA
MicrosoftMicrosoft Exchange Server 2019 Cumulative Update 815.02.0 to before 15.02.0792.01015.02.0792.010Patch availableCNA
  • Microsoft Exchange Server 2013 Cumulative Update 23 VendorMicrosoft Affected 15.00.0 to before 15.00.1497.012 Fixed in 15.00.1497.012 Patch available CNA
  • Microsoft Exchange Server 2016 Cumulative Update 18 VendorMicrosoft Affected 15.01.0 to before 15.01.2106.013 Fixed in 15.01.2106.013 Patch available CNA
  • Microsoft Exchange Server 2016 Cumulative Update 19 VendorMicrosoft Affected 15.01.0 to before 15.01.2176.009 Fixed in 15.01.2176.009 Patch available CNA
  • Microsoft Exchange Server 2019 Cumulative Update 7 VendorMicrosoft Affected 15.02.0 to before 15.02.0721.013 Fixed in 15.02.0721.013 Patch available CNA
  • Microsoft Exchange Server 2019 Cumulative Update 8 VendorMicrosoft Affected 15.02.0 to before 15.02.0792.010 Fixed in 15.02.0792.010 Patch available CNA

CPE configurations NVD · 5

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_18:*:*:*:*:*:*2016 cumulative_update_18VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*2016 cumulative_update_19VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:*2019 cumulative_update_7VulnerableMicrosoft
cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*2019 cumulative_update_8VulnerableMicrosoft
  • 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_18:*:*:*:*:*:* Versions 2016 cumulative_update_18 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:* Versions 2016 cumulative_update_19 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:* Versions 2019 cumulative_update_7 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:* Versions 2019 cumulative_update_8 Vulnerable ·Microsoft

Remediation

Microsoft 1 update

  • KB5000871
    Security Update
    • Microsoft Exchange Server 2013 Cumulative Update 21 15.00.1395.012
    • Microsoft Exchange Server 2013 Cumulative Update 22 15.00.1473.006
    • Microsoft Exchange Server 2013 Cumulative Update 23 15.00.1497.012
    • Microsoft Exchange Server 2013 Service Pack 1 15.00.0847.064
    • Microsoft Exchange Server 2016 Cumulative Update 10 15.01.1531.012
    • Microsoft Exchange Server 2016 Cumulative Update 11 15.01.1591.018
    • Microsoft Exchange Server 2016 Cumulative Update 12 15.01.1713.010
    • Microsoft Exchange Server 2016 Cumulative Update 13 15.01.1779.008
    • Microsoft Exchange Server 2016 Cumulative Update 14 15.01.1847.012
    • Microsoft Exchange Server 2016 Cumulative Update 15 15.01.1913.012
    • Microsoft Exchange Server 2016 Cumulative Update 16 15.01.1979.008
    • Microsoft Exchange Server 2016 Cumulative Update 17 15.01.2044.013
    • Microsoft Exchange Server 2016 Cumulative Update 18 15.01.2106.013
    • Microsoft Exchange Server 2016 Cumulative Update 19 15.01.2176.009
    • Microsoft Exchange Server 2016 Cumulative Update 8 15.01.1415.010
    • Microsoft Exchange Server 2016 Cumulative Update 9 15.01.1466.016
    • Microsoft Exchange Server 2019 15.02.0221.018
    • Microsoft Exchange Server 2019 Cumulative Update 1 15.01.1979.006
    • Microsoft Exchange Server 2019 Cumulative Update 2 15.02.0397.011
    • Microsoft Exchange Server 2019 Cumulative Update 3 15.02.0464.015
    • Microsoft Exchange Server 2019 Cumulative Update 4 15.02.0659.012
    • Microsoft Exchange Server 2019 Cumulative Update 5 15.02.0595.008
    • Microsoft Exchange Server 2019 Cumulative Update 6 15.02.0529.013
    • Microsoft Exchange Server 2019 Cumulative Update 7 15.02.0721.013
    • Microsoft Exchange Server 2019 Cumulative Update 8 15.02.0792.010

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Remote Code Execution
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Less Likely

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-26854
  2. 2026-10-03 Alias added: GHSA-2xf7-r7hp-r5qc

References

Patch 2

  • 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