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TI-2026-17152 Aliases CVE-2026-21243GHSA-843x-gmwc-22g8

Windows Lightweight Directory Access Protocol (LDAP) Denial of Service Vulnerability

Priority MEDIUM 42CWE-476Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

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

Summary

Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01409 72nd percentileScored 2026-11-07
Fix Fixed Microsoft: 6 updates

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftWindows Server 201910.0.17763.0 to before 10.0.17763.838910.0.17763.8389Patch availableCNA
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 to before 10.0.17763.838910.0.17763.8389Patch availableCNA
MicrosoftWindows Server 202210.0.20348.0 to before 10.0.20348.477310.0.20348.4773Patch availableCNA
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0 to before 10.0.25398.214910.0.25398.2149Patch availableCNA
MicrosoftWindows Server 202510.0.26100.0 to before 10.0.26100.3237010.0.26100.32370Patch availableCNA
MicrosoftWindows Server 2025 (Server Core installation)10.0.26100.0 to before 10.0.26100.3237010.0.26100.32370Patch availableCNA
  • Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8389 Fixed in 10.0.17763.8389 Patch available CNA
  • Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8389 Fixed in 10.0.17763.8389 Patch available CNA
  • Windows Server 2022 VendorMicrosoft Affected 10.0.20348.0 to before 10.0.20348.4773 Fixed in 10.0.20348.4773 Patch available CNA
  • Windows Server 2022, 23H2 Edition (Server Core installation) VendorMicrosoft Affected 10.0.25398.0 to before 10.0.25398.2149 Fixed in 10.0.25398.2149 Patch available CNA
  • Windows Server 2025 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.32370 Fixed in 10.0.26100.32370 Patch available CNA
  • Windows Server 2025 (Server Core installation) VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.32370 Fixed in 10.0.26100.32370 Patch available CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*before 10.0.17763.8389VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*before 10.0.20348.4711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*before 10.0.25398.2149VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*before 10.0.26100.32313VulnerableMicrosoft
  • cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* Versions before 10.0.17763.8389 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* Versions before 10.0.20348.4711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:* Versions before 10.0.25398.2149 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:* Versions before 10.0.26100.32313 Vulnerable ·Microsoft

Remediation

Microsoft 6 updates

  • KB5075943
    Security Hotpatch Update
    • Windows Server 2022 10.0.20348.4711
    • Windows Server 2022 (Server Core installation) 10.0.20348.4711
  • KB5075942
    Security Hotpatch Update
    • Windows Server 2025 10.0.26100.32313
    • Windows Server 2025 (Server Core installation) 10.0.26100.32313
  • KB5075906
    Security Update
    • Windows Server 2022 10.0.20348.4773
    • Windows Server 2022 (Server Core installation) 10.0.20348.4773
Show 3 more Microsoft updates
  • KB5075904
    Security Update
    • Windows 10 Version 1809 for 32-bit Systems 10.0.17763.8389
    • Windows 10 Version 1809 for x64-based Systems 10.0.17763.8389
    • Windows Server 2019 10.0.17763.8389
    • Windows Server 2019 (Server Core installation) 10.0.17763.8389
  • KB5075899
    Security Update
    • Windows Server 2025 10.0.26100.32370
    • Windows Server 2025 (Server Core installation) 10.0.26100.32370
  • KB5075897
    Security Update
    • Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2149

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Denial of Service
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation Unlikely

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21243
  2. 2026-10-03 Alias added: GHSA-843x-gmwc-22g8

References

Patch 1

  • TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-36863 Windows Server Update Service (WSUS) Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01431 Netlogon Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 10.0
  • TI-2020-01310 Improper input validation in Microsoft Windows Server KEVCVSS 3.1CRITICAL 10.0
  • TI-2026-73128 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2026-17367 MSHTML Framework Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
See all 6455 →

Sources

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