CVE-2026-21243

Published: Feb 10, 2026

Modified: May 11, 2026

PUBLISHED

CVSS v3.1

7.5

HIGH

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

Vendor	Product	Versions
Microsoft	Windows Server 2019	affected `10.0.17763.0 - < 10.0.17763.8389`
Microsoft	Windows Server 2019 (Server Core installation)	affected `10.0.17763.0 - < 10.0.17763.8389`
Microsoft	Windows Server 2022	affected `10.0.20348.0 - < 10.0.20348.4773`
Microsoft	Windows Server 2022, 23H2 Edition (Server Core installation)	affected `10.0.25398.0 - < 10.0.25398.2149`
Microsoft	Windows Server 2025	affected `10.0.26100.0 - < 10.0.26100.32370`
Microsoft	Windows Server 2025 (Server Core installation)	affected `10.0.26100.0 - < 10.0.26100.32370`

CVSS v3.1 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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

vendor-advisory

patch

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