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CVE-2026-40422Patch(microsoft / windows_10_1607)

MEDIUMCVSS 5.5 · MEDIUM

Exploitation ongoing with high activity in latest observed window (1 mentions)

Immediate actions

  • Patch microsoft windows_10_1607 systems immediately
  • Assume compromise if assets are exposed

Recommended action window: Immediate (within 24h)

NVD description

Use of uninitialized resource in Windows File Explorer allows an authorized attacker to disclose information locally.

microsoft CVEsBack to dashboard
4.5/ 10 priority

Sources & remediation

Vendor / third-party advisories
Weakness type (CWE)
CWE-908

Priority

MEDIUM

Exploitation

ACTIVE

PoC

NONE

Patch

AVAILABLE

Momentum

NONE

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

  • Active exploitation appears in 1 classified signals
  • Patch or workaround signal is available
  • 1 mentions across 1 observed day

What's happening

  • Active exploitation reported across 1 signal
  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 1 signal
  • 1 total mentions across 1 day

Affected systems

Vendors
microsoft
Products
windows_10_1607windows_10_1809windows_10_21h2windows_10_22h2windows_11_24h2windows_11_25h2windows_11_26h1windows_server_2016windows_server_2019windows_server_2022

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-07-15: 1Active Exploitation · 2026-07-15: 1Patch / Workaround · 2026-07-15: 1Technical Details · 2026-07-15: 107-15
Signal classification1 categories
Patch
1100.0%
Referenced assets1 URL
Full discourse1 post
  • Windows Forum@windowsforum
    Patch

    🪟 File Explorer was leaking data to attackers with local access. CVE-2026-40422 isn’t flashy, but “Important” is Microsoft-speak for “patch it before routine becomes incident response.” https://windowsforum.com/threads/cve-2026-40422-july-2026-updates-fix-windows-file-explorer-data-leak.438310/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #FileExplorer #WindowsSecurity #PatchTuesday #Cve202640422 https://t.co/tgBsWZxHxu

    Post summary

    CVE‑2026‑40422 causes data leakage via local access in Windows File Explorer, with evidence of active exploitation; a patch is available and Microsoft has marked it as Important.

    0000044
    1.2K followersView on X
CPE platform detail20 entries

20 of 20 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_24h2--arm64
OSmicrosoftwindows_11_24h2--x64
OSmicrosoftwindows_11_25h2--arm64
OSmicrosoftwindows_11_25h2--x64
OSmicrosoftwindows_11_26h1--arm64
OSmicrosoftwindows_11_26h1--x64
OSmicrosoftwindows_server_2016--x64
OSmicrosoftwindows_server_2019--x64
OSmicrosoftwindows_server_2022--x64
OSmicrosoftwindows_server_2025--x64

Explore more

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