CVE-2026-50472 — Windows LUA File Virtualization Filter Driver Elevation of Privilege Vulnerability

Executive Summary

Heap-based buffer overflow in Windows LUAFV allows an authorized attacker to elevate privileges locally.

Overview

7

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Elevation of Privilege

Weakness CWE-122: Heap-based Buffer Overflow

Released Aug 11 2026

Last Updated Aug 11 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00246 — 0.16012 percentile

NVD CVSS 7 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

ATTACK VECTOR

Local

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 6.1

EPSS Score

0.00246

probability of exploitation in the next 30 days

0.16012 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

22 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1607 for 32-bit Systems	`5120418 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1607 for x64-based Systems	`5120418 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for 32-bit Systems	`5120238 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for x64-based Systems	`5120238 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5120249 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5120249 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for x64-based Systems	`5120249 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5120249 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5120249 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for x64-based Systems	`5120249 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for ARM64-based Systems	`5120240 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for x64-based Systems	`5120240 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 24H2 for ARM64-based Systems 5120994 (Security Hotpatch Update) 5121003 (Security Update) Important Elevation of Privilege 5101650 Base: 7.0 Temporal: 6.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.9106 10.0.26100.9168 Yes None Windows 11 Version 24H2 for x64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Important Elevation of Privilege 5101650 Base: 7.0 Temporal: 6.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.9168 10.0.26000.9106 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Important Elevation of Privilege 5101650 Base: 7.0 Temporal: 6.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.9168 10.0.26100.9106 Yes None Windows 11 Version 25H2 for x64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Important Elevation of Privilege 5101650 Base: 7.0 Temporal: 6.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.9168 10.0.26100.9106 Yes None Windows 11 Version 26H1 for ARM64-based Systems	`5121000 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 version 26H1 for x64-based Systems	`5121000 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2012	`5120386 (Monthly Rollup)`	Important	Elevation of Privilege	Yes
Windows Server 2012 (Server Core installation)	`5120386 (Monthly Rollup)`	Important	Elevation of Privilege	Yes
Windows Server 2012 R2	`5120385 (Monthly Rollup)`	Important	Elevation of Privilege	Yes
Windows Server 2012 R2 (Server Core installation)	`5120385 (Monthly Rollup)`	Important	Elevation of Privilege	Yes
Windows Server 2016	`5120418 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2016 (Server Core installation)	`5120418 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019	`5120238 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019 (Server Core installation)	`5120238 (Security Update)`	Important	Elevation of Privilege	Yes

Patches

7 patches

Article	Type	Restart
`5120418`	Security Update	Yes
`5120238`	Security Update	Yes
`5120249`	Security Update	Yes
`5120240`	Security Update	Yes
`5121000`	Security Update	Yes
`5120386`	Monthly Rollup	Yes
`5120385`	Monthly Rollup	Yes

Patch Diff

ghidriff · luafv.sys (KB5121003)

Heap-based buffer overflow (CWE-122) via a race in the Windows LUA File Virtualization filter driver luafv.sys FileId-table node update, local EoP to SYSTEM (AC:H race). LUAFV virtualizes file access for legacy (LUA) apps and maintains a table of FileId nodes that cache per-file state including a path/name UNICODE_STRING (stored at node+0x50). UpdateTableNode refreshes a node from current file information (GetFileInformation) and, on failure, removed the node. PRE: the node-update path was insufficiently synchronized against concurrent update/removal of the same node, so a racing operation could update or reallocate the node's cached buffer while another path used it - a race leading to a heap buffer overflow of the node's allocation. Because luafv runs in the kernel and the virtualization path is reachable by a local user, and exploitation requires winning the race (AC:H), the overflow is a local EoP-to-SYSTEM primitive. Diff of luafv.sys 10.0.26100.8972 -> .9168 (Aug 11 2026, KB5121003) confirms the fix: gated behind CFR flag Feature_285200698, UpdateTableNode adds a name-match check (RtlCompareUnicodeString against the node name at +0x50) and gates the RemoveFileIdTableNode call so a node is not removed/reused out from under a concurrent update, and routes the node allocation through the LuafvAllocatePool wrapper instead of raw ExAllocatePool2. Note: UpdateTableNode is confirmed code-changed under Feature_285200698 with the added name-match/gated-removal/allocator changes; the exact overflowing write is not cleanly isolable in this race-hardening restructure, so the mechanism is stated per the CWE-122 + AC:H classification and the observed changes.

Pre-patch version 10.0.26100.8972 Download

Post-patch version 10.0.26100.9168 Download

Function	Address	Change	Note
`UpdateTableNode`	`code change`	code (race-hardened FileId-table node update, CFR-gated)	Pre: node update/removal on the FileId table node (name at +0x50) insufficiently synchronized -> racing update/realloc heap overflow. Post (Feature_285200698): adds RtlCompareUnicodeString name-match against node+0x50, gates the RemoveFileIdTableNode call, and allocates via LuafvAllocatePool instead of ExAllocatePool2.
`LuafvAllocatePool`	`call change`	now used for node allocation	UpdateTableNode now routes the node allocation through the LuafvAllocatePool wrapper (replacing a direct ExAllocatePool2).
`RemoveFileIdTableNode`	`call change`	invocation gated	Its removal call from UpdateTableNode is now conditioned under Feature_285200698 to avoid removing a node concurrently in use.
`Feature_285200698`	`gate`	added (CFR gate)	CFR flag gating the race-hardened node update; the original path still ships when disabled. (Feature_3287483706 / Feature_3614170424 also present in this update.)

View full diff report View RCA report

Attack Path

A concurrent update of a LUAFV FileId-table node races the node's removal/reallocation, overflowing its cached buffer

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

Exploits & PoC

No public exploit or PoC has been linked for this CVE yet. When available, references are sourced from public repositories and may be unverified or non-functional — review carefully before use.

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

Souhail Hammou

References

MSRC Advisory MITRE NVD