VulnSocial

CVE-2026-40399Disclosure(microsoft / windows_10_1607)

LOWCVSS 7.8 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP allows an authorized attacker to elevate privileges locally.

microsoft CVEsBack to dashboard
0.5/ 10 priority

Sources & remediation

Vendor / third-party advisories
Weakness type (CWE)
CWE-121

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

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

  • 1 mentions across 1 observed day

What's happening

  • Technical details provided in 1 signal
  • Disclosure: 1 classified signal
  • 1 total mentions across 1 day

Affected systems

Vendors
microsoft
Products
windows_10_1607windows_10_1809windows_10_21h2windows_10_22h2windows_11_23h2windows_11_24h2windows_11_25h2windows_11_26h1windows_server_2016windows_server_2019

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-05-12: 1Technical Details · 2026-05-12: 105-12
Signal classification1 categories
Disclosure
1100.0%
Referenced assets1 URL
Full discourse1 post
  • WindowsForum@windowsforum
    Disclosure

    🚨 CVE-2026-40399: “Windows TCP/IP” makes it sound remote… but it’s actually local PE to SYSTEM via a stack buffer overflow. Translation: if you’re already in, Microsoft says “congrats, admin.” https://windowsforum.com/threads/cve-2026-40399-windows-tcp-ip-local-privilege-escalation-to-system-may-12-2026.417840/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #PatchTuesday #LocalPrivilegeEscalation #Cve202640399 https://t.co/BTz2mtaS6k

    Post summary

    The tweet highlights CVE-2026-40399 as a local privilege‑escalation flaw in Windows TCP/IP caused by a stack buffer overflow, but does not provide PoC, exploit code, patches, or evidence of active attacks.

    0000042
    1.1K followersView on X
CPE platform detail23 entries

23 of 23 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_2016---
OSmicrosoftwindows_server_2019---
OSmicrosoftwindows_server_2022---
OSmicrosoftwindows_server_2022_23h2---
OSmicrosoftwindows_server_2025---

Explore more

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