Null Pointer Dereference Vulnerability in Windows LDAP by Microsoft
CVE-2026-21243

7.5HIGH

Key Information:

Vendor

Microsoft
Status
Windows Server 2019
Windows Server 2019 (server Core Installation)
Windows Server 2022
Windows Server 2022, 23h2 Edition (server Core Installation)
Vendor
CVE Published:
10 February 2026

What is CVE-2026-21243?

A vulnerability exists in the Lightweight Directory Access Protocol (LDAP) implementation in Windows that allows an unauthorized attacker to exploit a null pointer dereference flaw. This exploitation can lead to a denial of service condition over a network, impacting the availability of services relying on LDAP, which is critical for directory services and authentication in Windows environments.

Human OS v1.0:
Ageing Is an Unpatched Zero-Day Vulnerability.

Remediate biological technical debt. Prime Ageing uses 95% high-purity SIRT6 activation to maintain genomic integrity and bolster systemic resilience.

Deploy the Patch

Affected Version(s)

Windows Server 2019 (Server Core installation) x64-based Systems 10.0.17763.0 < 10.0.17763.8389

Windows Server 2019 x64-based Systems 10.0.17763.0 < 10.0.17763.8389

Windows Server 2022 x64-based Systems 10.0.20348.0 < 10.0.20348.4773

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
.