---
id: "CVE-2026-119834"
page: "https://infrastack.ai/live/CVE-2026-119834"
kind: "vulnerability"
aliases: ["CVE-2026-119834"]
title: "Windows Subsystem for Linux: heap overflow lets a local user gain higher privileges"
severity: "high"
cvss: 7.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "Windows 10 1809 / Server 2019", "fixed": ["10.0.17763.9487"], "affected": ">= 10.0.17763.0, < 10.0.17763.9487", "ecosystem": "vendor"}, {"name": "Windows 10 21H2", "fixed": ["10.0.19044.7846"], "affected": ">= 10.0.19044.0, < 10.0.19044.7846", "ecosystem": "vendor"}, {"name": "Windows 10 22H2", "fixed": ["10.0.19045.7846"], "affected": ">= 10.0.19045.0, < 10.0.19045.7846", "ecosystem": "vendor"}, {"name": "Windows 11 23H2", "fixed": ["10.0.22631.7711"], "affected": ">= 10.0.22631.0, < 10.0.22631.7711", "ecosystem": "vendor"}, {"name": "Windows 11 24H2", "fixed": ["10.0.26100.9974"], "affected": ">= 10.0.26100.0, < 10.0.26100.9974", "ecosystem": "vendor"}, {"name": "Windows 11 25H2", "fixed": ["10.0.26200.9974"], "affected": ">= 10.0.26200.0, < 10.0.26200.9974", "ecosystem": "vendor"}, {"name": "Windows 11 26H1", "fixed": ["10.0.28000.3501"], "affected": ">= 10.0.28000.0, < 10.0.28000.3501", "ecosystem": "vendor"}, {"name": "Windows 11 26H2", "fixed": ["10.0.26300.9974"], "affected": ">= 10.0.26300.0, < 10.0.26300.9974", "ecosystem": "vendor"}, {"name": "Windows Server 2022", "fixed": ["10.0.20348.5870"], "affected": ">= 10.0.20348.0, < 10.0.20348.5870", "ecosystem": "vendor"}, {"name": "Windows Server 2025", "fixed": ["10.0.26100.33822"], "affected": ">= 10.0.26100.0, < 10.0.26100.33822", "ecosystem": "vendor"}]
ecosystems: []
tags: ["infrastructure", "local-privilege-escalation", "local-users", "windows", "wsl"]
not_affected_if: ["no-local-users", "wsl-not-installed"]
published_at: "2026-11-10T19:19:59+00:00"
first_seen_at: "2026-11-10T19:24:58+00:00"
updated_at: "2026-11-10T22:48:56+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119834", "first_seen_at": "2026-11-10T19:24:58+00:00"}, {"source": "analyst", "url": "https://nvd.nist.gov/vuln/detail/cve-2026-119834", "first_seen_at": "2026-11-10T22:48:56+00:00", "cites": ["https://nvd.nist.gov/vuln/detail/cve-2026-119834", "https://radar.offseq.com/threat/cve-2026-119834-cwe-122-heap-based-buffer-overflow-in-microsoft-windows-10-version-1809-c3d4ba7de9d4af33"]}]
exploit_sources: []
---

# Windows Subsystem for Linux: heap overflow lets a local user gain higher privileges

Link for people: https://infrastack.ai/live/CVE-2026-119834 (this .md is for agents)

A heap-based buffer overflow in Windows Subsystem for Linux lets an attacker with a local low-privileged account gain higher privileges (CVSS 7.8). Microsoft's CNA data lists affected Windows builds, with fixes in the November 2026 updates.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Windows 10 1809 / Server 2019 affected >= 10.0.17763.0, < 10.0.17763.9487 fixed 10.0.17763.9487
- vendor:Windows 10 21H2 affected >= 10.0.19044.0, < 10.0.19044.7846 fixed 10.0.19044.7846
- vendor:Windows 10 22H2 affected >= 10.0.19045.0, < 10.0.19045.7846 fixed 10.0.19045.7846
- vendor:Windows 11 23H2 affected >= 10.0.22631.0, < 10.0.22631.7711 fixed 10.0.22631.7711
- vendor:Windows 11 24H2 affected >= 10.0.26100.0, < 10.0.26100.9974 fixed 10.0.26100.9974
- vendor:Windows 11 25H2 affected >= 10.0.26200.0, < 10.0.26200.9974 fixed 10.0.26200.9974
- vendor:Windows 11 26H1 affected >= 10.0.28000.0, < 10.0.28000.3501 fixed 10.0.28000.3501
- vendor:Windows 11 26H2 affected >= 10.0.26300.0, < 10.0.26300.9974 fixed 10.0.26300.9974
- vendor:Windows Server 2022 affected >= 10.0.20348.0, < 10.0.20348.5870 fixed 10.0.20348.5870
- vendor:Windows Server 2025 affected >= 10.0.26100.0, < 10.0.26100.33822 fixed 10.0.26100.33822

## How to check

Run winver or [System.Environment]::OSVersion.Version in PowerShell and compare the build with the fixed build for your release. Also run wsl --version to see whether WSL is installed; if absent or disabled you can likely skip. Whether a standalone Store WSL update is also needed is not stated in the sources.

## Fix

Install the November 2026 Windows update bringing the OS to at least: Win10 1809/Server 2019 10.0.17763.9487; Win10 21H2 10.0.19044.7846; Win10 22H2 10.0.19045.7846; Win11 23H2 10.0.22631.7711; Win11 24H2 10.0.26100.9974; Win11 25H2 10.0.26200.9974; Win11 26H1 10.0.28000.3501; Win11 26H2 10.0.26300.9974; Server 2022 10.0.20348.5870; Server 2025 10.0.26100.33822. Confirm against the MSRC advisory.

## Timeline

- 2026-11-10T19:24:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119834
- 2026-11-10T22:48:56+00:00 analyst https://nvd.nist.gov/vuln/detail/cve-2026-119834 — MSRC page is JS-only/unreadable; affected and fixed Windows builds from Microsoft CNA data mirrored on NVD, not the vendor page, so nothing verified. No exploitation or PoC found; not in KEV. Standalone WSL package version not stated.

## Documents

- [describes] NVD CVE-2026-119834 (Microsoft CNA affected builds) https://nvd.nist.gov/vuln/detail/cve-2026-119834
- [mentions] OffSeq Threat Radar CVE-2026-119834 https://radar.offseq.com/threat/cve-2026-119834-cwe-122-heap-based-buffer-overflow-in-microsoft-windows-10-version-1809-c3d4ba7de9d4af33

## From the sources

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

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