CVE-2026-21243 - Vulnerability Details - OpenCVE

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

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Vendors	Products
Microsoft	Windows Server 2019 Windows Server 2022 Windows Server 2025 Windows Server 23h2

No data.

No data.

No data.

References

Link	Providers
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21243

History

Tue, 10 Feb 2026 18:15:00 +0000

Type	Values Removed	Values Added
Description		Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.
Title		Windows Lightweight Directory Access Protocol (LDAP) Denial of Service Vulnerability
First Time appeared		Microsoft Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025 Microsoft windows Server 23h2
Weaknesses		CWE-476
CPEs		cpe:2.3:o:microsoft:windows_server_2019:::::::: cpe:2.3:o:microsoft:windows_server_2022:::::::: cpe:2.3:o:microsoft:windows_server_2025:::::::: cpe:2.3:o:microsoft:windows_server_23h2::::::::
Vendors & Products		Microsoft Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025 Microsoft windows Server 23h2
References		https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21243
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C'}`

MITRE

Status: PUBLISHED

Assigner: microsoft

Published: 2026-02-10T17:51:43.963Z

Updated: 2026-02-10T20:38:45.300Z

Reserved: 2025-12-11T21:02:05.735Z

Link: CVE-2026-21243

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-02-10T18:16:25.480

Modified: 2026-02-10T18:16:25.480

Link: CVE-2026-21243

Redhat

No data.

OpenCVE Enrichment

No data.

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