EUVD-2026-44019
GHSA-23r9-h96j-wj63
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Local authenticated access required (AV:L/PR:L); uninitialized read yields memory disclosure only, with no write or availability impact (C:H/I:N/A:N).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use of uninitialized resource in Windows SMB allows an authorized attacker to disclose information locally.
AnalysisAI
Information disclosure via uninitialized memory in the Windows SMB driver stack affects a broad range of Windows 10, Windows 11, and Windows Server versions. A locally authenticated, low-privileged attacker can trigger a code path that reads from uninitialized memory within the SMB subsystem, potentially leaking sensitive kernel or heap memory contents. No public exploit code or active exploitation has been identified at the time of analysis; Microsoft has released a patch via MSRC.
Technical ContextAI
The vulnerability is rooted in CWE-908 (Use of Uninitialized Resource), a class of flaw where a software component reads from a memory buffer before that buffer has been explicitly initialized, potentially exposing arbitrary memory contents to the caller. The affected component is the Windows SMB (Server Message Block) driver stack - the core file-sharing and IPC transport present in virtually all Windows installations. Despite SMB being fundamentally a network protocol, the CVSS attack vector is local (AV:L), indicating the exploitable code path is reachable through a local API or ioctl call into the SMB driver (e.g., mrxsmb.sys or srvnet.sys) rather than directly over the network. Affected CPEs span Windows 10 versions 1607 through 22H2, Windows 11 versions 24H2, 25H2, and 26H1, and Windows Server 2012 through 2025 including Server Core installations.
RemediationAI
Apply the vendor-released patch from the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54997. The input data confirms a patch is available but does not specify an exact patched build version; consult the MSRC advisory directly to identify the specific KB article and build number for each affected Windows version. As a compensating control where patching is not immediately possible, restricting local interactive and remote desktop access to only explicitly authorized administrative personnel reduces the pool of potential attackers, since exploitation requires local authenticated access (PR:L, AV:L). Disabling SMB entirely is not a practical workaround for most environments given its role in file sharing and authentication, but organizations with strict network segmentation can restrict SMB-based local driver access through AppLocker or WDAC policies to limit attack surface. Note that these compensating controls address exposure, not the underlying flaw.
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Same weakness CWE-908 – Use of Uninitialized Resource
View allSame technique Information Disclosure
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External POC / Exploit Code
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