EUVD-2026-43918
GHSA-4gmx-836j-jvhf
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Description states unauthenticated network information disclosure, so AV:N/PR:N/UI:N; impact is confidentiality-only (C:H) with no integrity or availability effect.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Out-of-bounds read in Windows Kernel allows an unauthorized attacker to disclose information over a network.
AnalysisAI
Information disclosure in the Windows Kernel allows a remote, unauthenticated attacker to read out-of-bounds memory and leak sensitive data across all currently supported Windows client and server builds (Windows 10 1809/21H2/22H2, Windows 11 24H2/25H2/26H1, and Windows Server 2019/2022/2025). The CVSS 3.1 base score is 7.5 (AV:N/AC:L/PR:N/UI:N, high confidentiality impact only). There is no public exploit identified at time of analysis and it is not listed in CISA KEV, but the network-reachable, no-privilege, no-interaction profile makes it a broadly applicable patch-now item.
Technical ContextAI
The flaw is a CWE-125 out-of-bounds read in the Windows Kernel, the core ring-0 component that manages memory, scheduling, and I/O for the operating system. Out-of-bounds reads occur when code processes attacker-influenced length or offset values without proper bounds validation, causing it to read memory beyond the intended buffer and return that adjacent kernel or process memory to the attacker. Because the fault is in the kernel rather than a user-mode service, leaked bytes may include sensitive kernel structures or memory that aids defeating protections such as KASLR. The CPE data confirms this affects the base Microsoft Windows OS across the 10/11 client families and Server 2019/2022/2025, i.e. the kernel shipped with those SKUs rather than a specific optional feature or add-on component.
RemediationAI
Apply the Microsoft security update for CVE-2026-50463; the vendor advisory confirms a patch is available, and the exact fixed build numbers per SKU should be taken directly from Microsoft's Security Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50463 (specific fixed version not enumerated in the supplied data, so do not substitute an assumed build). Prioritize deployment on internet-exposed and multi-tenant servers (Windows Server 2019/2022/2025) where the network attack surface is greatest, then roll out to Windows 10 and 11 clients via your normal patch pipeline. No official workaround is provided; as compensating controls until patching, restrict network exposure of the affected kernel-facing services by segmenting and firewalling the relevant ports/protocols and limiting reachability of Windows hosts from untrusted networks, accepting that such filtering may disrupt legitimate remote services and does not fully remove the flaw. Because the bug is in the kernel itself, disabling an individual application feature is not a reliable mitigation, so treat patching as the definitive fix.
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Same weakness CWE-125 – Out-of-bounds Read
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today