EUVD-2026-43796
GHSA-2hwx-q2mm-644r
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Network-reachable AD DS with low complexity and no user interaction, but requires an authenticated low-privileged foothold (PR:L); code execution on the DC yields high C/I/A.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Active Directory Domain Services allows an authorized attacker to execute code over a network.
AnalysisAI
Remote code execution in Microsoft Active Directory Domain Services (AD DS) allows an authenticated network attacker to run arbitrary code on domain controllers by triggering a heap-based buffer overflow (CWE-122). Affected platforms span Windows Server 2012 through 2025 (including Server Core) and Windows 10/11 clients acting in AD roles, with Microsoft-issued patches available. There is no public exploit identified at time of analysis and it is not on CISA KEV, but the CVSS 8.8 rating and the sensitivity of the domain-controller attack surface make this a high-priority patch.
Technical ContextAI
Active Directory Domain Services is the directory and authentication backbone of Windows enterprise networks, exposing LDAP, Kerberos, RPC, and replication services over the network from domain controllers. The flaw is classified CWE-122 (heap-based buffer overflow), meaning attacker-controlled input is written past the bounds of a dynamically allocated heap buffer within an AD DS component, corrupting adjacent heap memory (allocation metadata, function pointers, or object state) and enabling control-flow hijack and code execution. The affected CPEs enumerate Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025 (including Server Core installations) plus Windows 10 (1607/1809/21H2/22H2) and Windows 11 (24H2/25H2/26H1), indicating the vulnerable code path ships across the broad Windows/AD DS codebase rather than a single release.
RemediationAI
Apply the Microsoft security update for CVE-2026-49178 to all affected domain controllers and Windows systems; the fix is available per the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49178 (Patch available per vendor advisory - cross-reference that page for the exact per-OS patched build, which is not enumerated in the available data). Prioritize domain controllers first, including Server Core installations. Because exploitation requires an authenticated network foothold, meaningful interim compensating controls include tightening which accounts can reach domain-controller services and enforcing network segmentation so that only management and member hosts can initiate AD DS/LDAP/RPC traffic to DCs (trade-off: overly aggressive filtering of DC RPC/LDAP can break authentication, replication, and Group Policy, so test firewall rules against AD's required ports before enforcing). Reducing the number of low-privileged accounts and auditing anomalous DC-directed traffic further shrinks the reachable attacker pool until patching is complete.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today