EUVD-2026-44002
GHSA-92hv-9549-833x
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local authenticated low-priv user (AV:L/PR:L) exploits default-loaded kernel driver with no interaction (AC:L/UI:N); leaked kernel data chains to SYSTEM giving full C:H/I:H/A:H.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Exposure of sensitive information to an unauthorized actor in Windows Common Log File System Driver allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Common Log File System (CLFS) Driver allows an already-authenticated, low-privileged user to elevate to SYSTEM on a wide range of Windows client and server releases. Microsoft classifies the root cause as exposure of sensitive information (CWE-200), but the CVSS impact profile (C:H/I:H/A:H) reflects that the leaked kernel data enables full local privilege escalation. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, though CLFS has historically been a heavily exploited elevation-of-privilege target in Windows.
Technical ContextAI
The Common Log File System (clfs.sys) is a kernel-mode general-purpose logging subsystem built into Windows and used by many components and applications to create transactional log files. Because CLFS runs in the kernel and parses complex on-disk log (BLF) structures, flaws in it are directly reachable from user mode and yield kernel-level impact. This CVE is categorized as CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), meaning the driver discloses privileged kernel memory content to a lower-privileged context; that disclosed data (for example kernel pointers or token/heap state) can be used to defeat mitigations such as KASLR and drive a reliable privilege-escalation exploit. The affected code is the CLFS driver shipped across Windows 10 (1607 through 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2012 through 2025, including Server Core installations.
RemediationAI
Apply the Microsoft security update for your specific Windows SKU as the primary and definitive fix; Patch available per vendor advisory, with per-SKU fixed builds listed at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50697 (the exact fix version string was not included in this dataset and should be taken from that page). Prioritize deployment on multi-user, RDP/terminal, and internet-facing servers where an attacker who gains any low-privileged foothold could immediately escalate. Because the vulnerability lives in the always-loaded kernel CLFS driver, there is no supported feature toggle or configuration workaround - CLFS cannot simply be disabled - so patching is the only reliable control; compensating measures until patching is complete are limited to reducing local attacker footholds: enforce least privilege, restrict interactive/RDP logon rights, deploy EDR to detect suspicious CLFS BLF manipulation and token-swapping behavior, and apply application allow-listing to slow initial code execution. Note these controls reduce the probability of reaching the vulnerable code but do not remove the flaw.
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Same weakness CWE-200 – Information Exposure
View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today