VulnSocial

CVE-2026-40397Patch(microsoft / windows_10_1607)

LOWCVSS 7.8 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch microsoft windows_10_1607 systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

Heap-based buffer overflow in Windows Common Log File System Driver allows an authorized attacker to elevate privileges locally.

microsoft CVEsBack to dashboard
1.0/ 10 priority

Sources & remediation

Vendor / third-party advisories
Weakness type (CWE)
CWE-191

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • windows_10_1607
  • windows_10_1809
  • windows_10_21h2
  • windows_10_22h2

Threat summary

  • Patch or workaround signal is available
  • 3 mentions across 3 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 3 signals
  • Disclosure: 1 classified signal
  • General: 1 classified signal
  • Peaked 2d ago at 1 mentions (2026-05-12); latest day: 1
  • 3 total mentions across 3 days

Affected systems

Vendors
microsoft
Products
windows_10_1607windows_10_1809windows_10_21h2windows_10_22h2windows_11_23h2windows_11_24h2windows_11_25h2windows_11_26h1windows_server_2012windows_server_2016

2 versions affected across 14 products

Deep dive

Activity timeline3 mentions / 3d
00111Mentions · 2026-05-12: 1Mentions · 2026-05-13: 1Mentions · 2026-05-21: 1Patch / Workaround · 2026-05-12: 1Technical Details · 2026-05-12: 1Technical Details · 2026-05-13: 1Technical Details · 2026-05-21: 105-1205-1305-21
Signal classification3 categories
Patch
133.3%
Disclosure
133.3%
General
133.3%
Referenced assets2 URLs
Classification over time
DateTotalLabels
2026-05-121
Patch1
2026-05-131
Disclosure1
2026-05-211
General1
Full discourse3 posts
  • STEALIEN@stealien
    General

    Diffuto CVE 분석 리포트 #002 | CVE-2026-40397 https://ufo.stealien.com/2026-05-21/CVE-2026-40397-analysis-ko #Diffuto #사이버보안 #취약점분석 #Windows #CVE Windows CLFS 권한 상승 취약점 분석 AI 기반 취약점 분석 엔진 Diffuto가 Patch Diff 기반 분석을 통해 취약점 발생 원인과 패치 흐름을 추적했습니다. https://t.co/zjvfkMgLsS

    Post summary

    The tweet introduces a Diffuto analysis report on CVE-2026-40397, a Windows CLFS privilege‑escalation flaw, but offers no PoC, exploit, active‑use evidence, or patch details.

    02041353
    510 followersView on X
  • kawn@kawn2020
    Disclosure

    #windowsupdate #microsoft つづき ・CVE-2026-40361　8.4　Microsoft Office Word ・CVE-2026-40364　8.4　Microsoft Office Word ・CVE-2026-40369　7.8　Windows カーネル ・CVE-2026-40397　7.8　Windows 共通ログ ファイル システム ドライバー つづく…

    Post summary

    The tweet lists several newly disclosed CVEs affecting Microsoft Office Word and Windows system components, including CVSS scores, but provides no further details on exploitation, patches, or PoCs.

    10000155
    85 followersView on X
  • WindowsForum@windowsforum
    Patch

    🪟 CVE-2026-40397 in CLFS = Windows “logging” that could log you straight into SYSTEM. Not panic, but definitely don’t ignore this one—patch like it’s zero-day. #Windows #Security https://windowsforum.com/threads/cve-2026-40397-may-patch-tuesday-fix-for-windows-clfs-privilege-escalation.417966/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #PrivilegeEscalation #PatchTuesday #WindowsClfs #Cve202640397 https://t.co/tC35mDUZrY

    Post summary

    The post highlights that CVE‑2026‑40397 is a Windows CLFS privilege‑escalation flaw capable of granting SYSTEM rights, and urges users to apply the upcoming Patch Tuesday fix.

    0000060
    1.1K followersView on X
CPE platform detail25 entries

25 of 25 entries

PartVendorProductVersionTarget SWTarget HW
OSmicrosoftwindows_10_1607--x64
OSmicrosoftwindows_10_1607--x86
OSmicrosoftwindows_10_1809--x64
OSmicrosoftwindows_10_1809--x86
OSmicrosoftwindows_10_21h2--arm64
OSmicrosoftwindows_10_21h2--x64
OSmicrosoftwindows_10_21h2--x86
OSmicrosoftwindows_10_22h2--arm64
OSmicrosoftwindows_10_22h2--x64
OSmicrosoftwindows_10_22h2--x86
OSmicrosoftwindows_11_23h2--arm64
OSmicrosoftwindows_11_23h2--x64
OSmicrosoftwindows_11_24h2--arm64
OSmicrosoftwindows_11_24h2--x64
OSmicrosoftwindows_11_25h2--arm64
OSmicrosoftwindows_11_25h2--x64
OSmicrosoftwindows_11_26h1--arm64
OSmicrosoftwindows_11_26h1--x64
OSmicrosoftwindows_server_2012---
OSmicrosoftwindows_server_2012r2--
OSmicrosoftwindows_server_2016---
OSmicrosoftwindows_server_2019---
OSmicrosoftwindows_server_2022---
OSmicrosoftwindows_server_2022_23h2---
OSmicrosoftwindows_server_2025---

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