CVE-2026-21243

Name: CVE-2026-21243
Creator: NVD / NIST
Published: 2026-02-10T18:16:25.48+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.34%

Last modified Jun 17, 2026

CVE-2026-21243 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.. EPSS estimates a 1.34% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.34%

67.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-476

Affected Software

Vendor	Product	Versions
Microsoft	Windows Server 2019	< 10.0.17763.8389
Microsoft	Windows Server 2022	< 10.0.20348.4711
Microsoft	Windows Server 2022 23h2	< 10.0.25398.2149
Microsoft	Windows Server 2025	< 10.0.26100.32313

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21243Vendor Advisory

Timeline

Published: Feb 10, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-21243?

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 a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.34% probability of exploitation in the next 30 days.

How do I fix CVE-2026-21243?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-21243?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST