Unauthenticated code execution via unchecked Unicode terminator
Published May 12, 2026 · Updated May 12, 2026
Stack-based buffer overflow in Microsoft Windows Netlogon allows remote attackers to execute code on domain controllers over a network. NetpLogonPutUnicodeString writes a two-byte terminator after its bounded copy loop without verifying remaining space while assembling a CLDAP reply in a 528-byte stack buffer. Exploitation requires an unpatched Windows Server domain controller and a crafted UDP 389 LDAP ping whose serialized names and User field exhaust that buffer; successful corruption runs code as SYSTEM.
Summary
What happened
Stack-based buffer overflow in Microsoft Windows Netlogon allows remote attackers to execute code on domain controllers over a network. NetpLogonPutUnicodeString writes a two-byte terminator after its bounded copy loop without verifying remaining space while assembling a CLDAP reply in a 528-byte stack buffer. Exploitation requires an unpatched Windows Server domain controller and a crafted UDP 389 LDAP ping whose serialized names and User field exhaust that buffer; successful corruption runs code as SYSTEM.
The record
- CVE
- CVE-2026-41089
- Published
- May 12, 2026
- Updated
- May 12, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-121, T1210
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 12, 2026CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.8755
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- CVE-2026-41089 Netlogon CLDAP proof of conceptfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- CCB-reported active exploitationreported exploitation
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo