EUVD-2026-43985
GHSA-rmfg-jhvq-w5r5
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Description states local privilege elevation by an authorized attacker, so AV:L and PR:L; low complexity and full host compromise give AC:L and C/I/A:H with unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Windows DNS allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in Microsoft Windows DNS lets an already-authenticated, low-privileged attacker corrupt heap memory to gain higher (likely SYSTEM) privileges on affected Windows 10, Windows 11, and Windows Server 2022/2025 systems. The flaw is a heap-based buffer overflow (CWE-122) reported by Microsoft itself, with a vendor patch available via MSRC. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, so it currently represents a patch-priority rather than an emergency.
Technical ContextAI
The vulnerability lives in the Windows DNS component (the DNS Server role and/or associated DNS resolution code shipped with Windows client and server SKUs). CWE-122 (heap-based buffer overflow) indicates that attacker-influenced data is written past the bounds of a dynamically allocated heap buffer, corrupting adjacent heap structures. Successful heap grooming and overflow can overwrite function pointers or object metadata, allowing an attacker to redirect execution or manipulate privileged data structures. Per the CPE data the flaw spans Windows 10 (21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2022 and 2025 including Server Core installations, indicating the vulnerable code is in a broadly shared Windows DNS binary rather than an edition-specific feature.
RemediationAI
Apply the Microsoft security update for CVE-2026-49175 (Patch available per vendor advisory) referenced at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49175; install the corresponding monthly cumulative update for each affected SKU, prioritizing Windows Server 2022/2025 hosts running the DNS Server role and any multi-user or session-host systems where local footholds are likely. Exact fixed build numbers are listed per edition in the MSRC entry - deploy them via Windows Update, WSUS, or your patch management tooling. Because exploitation is local and requires an existing low-privileged account, in the interim reduce risk by tightening local logon and interactive-session access, removing unnecessary local accounts, and restricting who can run code on DNS servers and domain infrastructure; note these are access-hardening controls that limit the pool of potential attackers but do not remove the underlying overflow, so patching remains the only definitive fix.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
Leaving vuln.today