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HIGH · 7.5

CVE-2026-21243

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

Vulnerability Description

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

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
MicrosoftWindows Server 2019< 10.0.17763.8389
MicrosoftWindows Server 2022< 10.0.20348.4711
MicrosoftWindows Server 2022 23H2< 10.0.25398.2149
MicrosoftWindows Server 2025< 10.0.26100.32313

Related Weaknesses (CWE)

CWE-476

References

FAQ

What is CVE-2026-21243?

CVE-2026-21243 is a vulnerability with a CVSS score of 7.5 (HIGH). Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.

How severe is CVE-2026-21243?

CVE-2026-21243 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-21243?

Check the references section above for vendor advisories and patch information. Affected products include: Microsoft Windows Server 2019, Microsoft Windows Server 2022, Microsoft Windows Server 2022 23H2, Microsoft Windows Server 2025.