Windows LDAP - Lightweight Directory Access Protocol
CVE-2026-21243 — Windows Lightweight Directory Access Protocol (LDAP) Denial of Service Vulnerability
Executive Summary
Null pointer dereference in Windows LDAP - Lightweight Directory Access Protocol allows an unauthorized attacker to deny service over a network.
Overview
7.5
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Exploitation Unlikely
MS Exploit Likelihood
CVSS Vector
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
Temporal Score: 6.5
EPSS Score
0.0134
probability of exploitation in the next 30 days
0.67615 percentile - updated 2026-06-20
View on FIRST.org
Affected Products
7 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows Server 2019 | 5075904 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2019 (Server Core installation) | 5075904 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2022 | 5075906 (Security Update) 5075943 (Security Hotpatch Update) |
Important | Denial of Service | Yes |
| Windows Server 2022 (Server Core installation) | 5075906 (Security Update) 5075943 (Security Hotpatch Update) |
Important | Denial of Service | Yes |
| Windows Server 2022, 23H2 Edition (Server Core installation) | 5075897 (Security Update) |
Important | Denial of Service | Yes |
| Windows Server 2025 | 5075899 (Security Update) 5075942 (Security Hotpatch Update) |
Important | Denial of Service | Yes |
| Windows Server 2025 (Server Core installation) | 5075899 (Security Update) 5075942 (Security Hotpatch Update) |
Important | Denial of Service | Yes |
Patches
4 patches
| Article | Type | Restart |
|---|---|---|
5075904 |
Security Update | Yes |
5075906 (Security Update) 5075943 |
Security Update | Yes |
5075897 |
Security Update | Yes |
5075899 (Security Update) 5075942 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
MORSE (Microsoft Offensive Research and Security Engineering)
References
On This Page