---
id: "CVE-2026-119816"
page: "https://infrastack.ai/live/CVE-2026-119816"
kind: "vulnerability"
aliases: ["CVE-2026-119816"]
title: "Windows: Microsoft Account Sign-in Assistant heap overflow allows local privilege escalation"
severity: "high"
cvss: 7.8
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Account Sign-in Assistant", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["infrastructure", "local-privilege-escalation", "microsoft-account", "windows"]
not_affected_if: ["no-local-untrusted-users"]
published_at: "2026-11-10T19:19:56+00:00"
first_seen_at: "2026-11-10T19:24:57+00:00"
updated_at: "2026-11-10T22:52:14+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119816", "first_seen_at": "2026-11-10T19:24:57+00:00"}, {"source": "analyst", "url": "https://api.msrc.microsoft.com/sug/v2.0/en-US/vulnerability/CVE-2026-119816", "first_seen_at": "2026-11-10T22:52:14+00:00", "cites": ["https://api.msrc.microsoft.com/sug/v2.0/en-US/vulnerability/CVE-2026-119816"]}]
exploit_sources: []
---

# Windows: Microsoft Account Sign-in Assistant heap overflow allows local privilege escalation

Link for people: https://infrastack.ai/live/CVE-2026-119816 (this .md is for agents)

Microsoft fixed a heap-based buffer overflow (CWE-122) in the Windows Microsoft Account Sign-in Assistant in the November 2026 Patch Tuesday (10 Nov 2026). A local attacker with low privileges can gain SYSTEM. Microsoft rates it Important (CVSS 7.8), not publicly disclosed, not exploited, 'Exploitation Unlikely'. The per-Windows-version builds and KB numbers were not available to me, so they are unknown.

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

## Affected

- vendor:Microsoft Account Sign-in Assistant affected range not listed fixed no fixed version listed

## How to check

Check that the November 2026 cumulative update (released 10 Nov 2026) is installed on each Windows machine. The exact KB and build for this CVE are unknown; look it up under CVE-2026-119816 in the MSRC Security Update Guide.

## Fix

Install the November 2026 Windows security update (Patch Tuesday, 10 Nov 2026). The exact KB per Windows version is unknown.

## Timeline

- 2026-11-10T19:24:57+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119816
- 2026-11-10T22:52:14+00:00 analyst https://api.msrc.microsoft.com/sug/v2.0/en-US/vulnerability/CVE-2026-119816 — MSRC record (API) read: Important, CVSS 7.8, local, SYSTEM, Exploitation Unlikely, not exploited/disclosed. Affected builds and KBs not in the record I could read (MSRC page is JS-only); left unknown.

## Documents

- [advisory] MSRC Security Update Guide: CVE-2026-119816 (API record) https://api.msrc.microsoft.com/sug/v2.0/en-US/vulnerability/CVE-2026-119816

## From the sources

Heap-based buffer overflow in Windows Microsoft Account Sign-in Assistant allows an authorized attacker to elevate privileges locally.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_