EUVD-2026-44082
GHSA-fp27-2rx6-gvr6
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Network-reachable DC service, low complexity, no auth or interaction (AV:N/AC:L/PR:N/UI:N); availability-only crash (A:H) with no confidentiality or integrity impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Untrusted pointer dereference in Windows Domain Controller allows an unauthorized attacker to deny service over a network.
AnalysisAI
Denial of service in the Windows Domain Controller role on Windows Server 2025 (including Server Core) and Windows 11 24H2/25H2/26H1 lets a remote, unauthenticated attacker crash or hang authentication services by triggering an untrusted pointer dereference over the network. Because the CVSS vector is PR:N/UI:N with A:H and no confidentiality or integrity impact, a single crafted network exchange can disrupt directory and logon services domain-wide without credentials. No public exploit identified at time of analysis, and it is not on CISA KEV; Microsoft has released a patch.
Technical ContextAI
The flaw is classified as CWE-822 (Untrusted Pointer Dereference): code takes a pointer value that is influenced by attacker-controlled input and dereferences it without validating that it points to a legitimate, allocated object, causing an invalid memory access and process fault. It resides in the Windows Domain Controller role - the Active Directory / authentication service that Windows Server domain controllers expose over the network (Kerberos, LDAP, Netlogon and RPC-family protocols). Per the CPE data the affected code ships in Windows Server 2025 and Windows Server 2025 Server Core, and Microsoft also lists the Windows 11 client builds 24H2, 25H2 and 26H1 as carrying the vulnerable component. When the untrusted pointer is dereferenced the service faults, which for a DC translates directly into loss of availability for domain logons.
RemediationAI
Apply the Microsoft security update for CVE-2026-50424 (patch available per vendor advisory) via Windows Update / WSUS to all domain controllers and to Windows 11 24H2, 25H2 and 26H1 systems, prioritizing broadly-reachable domain controllers first; exact fixed build numbers are in the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50424. Because domain controllers cannot practically disable the authentication protocols the flaw lives in, patching is the only reliable fix; as an interim compensating control, restrict network reachability of DC service ports (Kerberos 88, LDAP 389/636, RPC/Netlogon endpoint mapper 135 and the dynamic RPC range, SMB 445) to trusted internal management and member-host subnets via host or perimeter firewalls so untrusted networks cannot reach the DC, accepting the trade-off that overly tight filtering can break legitimate client logons, replication or trusts and must be validated before enforcement. Maintain redundant domain controllers so a single crashed DC does not halt domain authentication.
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Same weakness CWE-822 – Untrusted Pointer Dereference
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today