CVE-2026-21243HighCVSS 7.5
Windows Lightweight Directory Access Protocol (LDAP) Denial of Service Vulnerability
🔗 CVE IDs covered (1)
📋 Description
Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.
🎯 Affected products7
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows Server 2022
- Windows Server 2022 (Server Core installation)
- Windows Server 2022, 23H2 Edition (Server Core installation)
- Windows Server 2025
- Windows Server 2025 (Server Core installation)
✅ Remediation
KB5075904 (Security Update) — fixed build 10.0.17763.8389 KB5075906 (Security Update) — fixed build 10.0.20348.4773 KB5075943 (Security Hotpatch Update) — fixed build 10.0.20348.4711 KB5075899 (Security Update) — fixed build 10.0.26100.32370 KB5075942 (Security Hotpatch Update) — fixed build 10.0.26100.32313 KB5075897 (Security Update) — fixed build 10.0.25398.2149
🔗 References (13)
- advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21243
- patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075904
- referencehttps://support.microsoft.com/help/5075904
- patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075906
- referencehttps://support.microsoft.com/help/5075906
- patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075943
- referencehttps://support.microsoft.com/help/5075943
- patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075899
- referencehttps://support.microsoft.com/help/5075899
- patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075942
- referencehttps://support.microsoft.com/help/5075942
- patchhttps://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075897
- referencehttps://support.microsoft.com/help/5075897