CVE-2026-21243
Windows Lightweight Directory Access Protocol (LDAP) Denial of Service Vulnerability
CVE-2026-21243 is fixed in 7 products on 1 platform, first by KB5075904, released February 10, 2026. It is not reported as exploited. Patch Radar priority: High.
High
CVSS
7.5
Important
Exploitation
None reported
Exploitation Unlikely
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0141
72nd percentile
<p>Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.</p>
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Microsoft | |||
| Windows Server 2019 | 17763.8389 | KB5075904 | Feb 10, 2026 |
| Windows Server 2019 (Server Core installation) | 17763.8389 | KB5075904 | Feb 10, 2026 |
| Windows Server 2022 | 20348.4773 | KB5075906 | Feb 10, 2026 |
| Windows Server 2022 | 20348.4711 | KB5075943 | Feb 10, 2026 |
| Windows Server 2022 (Server Core installation) | 20348.4773 | KB5075906 | Feb 10, 2026 |
| Windows Server 2022 (Server Core installation) | 20348.4711 | KB5075943 | Feb 10, 2026 |
| Windows Server 2022, 23H2 Edition (Server Core installation) | 25398.2149 | KB5075897 | Feb 10, 2026 |
| Windows Server 2025 | 26100.32313 | KB5075942 | Feb 10, 2026 |
| Windows Server 2025 | 26100.32370 | KB5075899 | Feb 10, 2026 |
| Windows Server 2025 (Server Core installation) | 26100.32313 | KB5075942 | Feb 10, 2026 |
| Windows Server 2025 (Server Core installation) | 26100.32370 | KB5075899 | Feb 10, 2026 |
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