CVE-2026-40398Disclosure(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 Remote Desktop allows an authorized attacker to elevate privileges locally.

1.0/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-122

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
  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

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

Affected systems

Vendors
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 timeline2 mentions / 2d
00111Mentions · 2026-05-12: 1Mentions · 2026-05-13: 1Patch / Workaround · 2026-05-12: 1Technical Details · 2026-05-12: 1Technical Details · 2026-05-13: 105-1205-13
Signal classification2 categories
Disclosure
150.0%
General
150.0%
Referenced assets1 URL
Classification over time
DateTotalLabels
2026-05-121
Disclosure1
2026-05-131
General1
Full discourse2 posts
  • kawn@kawn2020
    General

    #windowsupdate #microsoft つづき ・CVE-2026-40398 7.8 Windows リモート デスクトップ ・CVE-2026-41103 9.1 Jira と Confluence 用の Microsoft SSO プラグイン -対象外:10 件 ・CVE-2026-26129 7.5 M365 Copilot つづく…

    Post summary

    The tweet lists several Microsoft-related CVEs with severity scores but lacks any discussion of PoC, exploits, patches, or deeper technical details.

    10000107
    85 followersView on X
  • WindowsForum@windowsforum
    Disclosure

    🚨 CVE-2026-40398 is “Important” RDS privilege escalation: not wormable, but still Windows letting the network punch up. RDS = trust boundary, patch fast. #Windows #Security https://windowsforum.com/threads/cve-2026-40398-windows-rds-privilege-escalation-important-cvss-7-8.417972/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #PrivilegeEscalation #PatchTuesday #WindowsRds #Cve202640398 https://t.co/55GgcAWBFJ

    Post summary

    The post announces CVE‑2026‑40398 as an important Windows RDS privilege escalation flaw with CVSS 7.8, notes it is not wormable but still risky, and urges users to patch quickly.

    0000028
    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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