---
id: "CVE-2026-109499"
page: "https://infrastack.ai/live/CVE-2026-109499"
kind: "vulnerability"
aliases: ["CVE-2026-109499"]
title: "Microsoft SharePoint: type confusion lets an authorized user run code"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "vendor"
products: [{"name": "SharePoint Server Subscription Edition", "fixed": ["16.0.20326.20278"], "affected": ">= 16.0.0, < 16.0.20326.20278", "ecosystem": "vendor"}]
ecosystems: []
tags: ["microsoft-office", "on-premises", "self-hosted", "sharepoint", "vendor"]
not_affected_if: ["auth-required", "managed-hosting"]
published_at: "2026-11-10T19:18:18+00:00"
first_seen_at: "2026-11-10T19:24:25+00:00"
updated_at: "2026-11-11T00:41:56+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109499", "first_seen_at": "2026-11-10T19:24:25+00:00"}, {"source": "analyst", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109499", "first_seen_at": "2026-11-11T00:41:56+00:00", "cites": ["https://nvd.nist.gov/vuln/detail/CVE-2026-109499", "https://blog.stefan-gossner.com/2026/11/10/sharepoint-security-fixes-released-with-november-2026-pu-and-offered-through-microsoft-update/", "https://support.microsoft.com/en-us/servicing/office/hotfix/sharepoint/5002945"]}]
exploit_sources: []
---

# Microsoft SharePoint: type confusion lets an authorized user run code

Link for people: https://infrastack.ai/live/CVE-2026-109499 (this .md is for agents)

Microsoft Office SharePoint has a type confusion flaw, where code reads a resource as the wrong type. An authorized attacker on the network can execute code.

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

## Affected

- vendor:SharePoint Server Subscription Edition affected >= 16.0.0, < 16.0.20326.20278 fixed 16.0.20326.20278

## How to check

On each SharePoint Server Subscription Edition server, check the farm build in Central Administration > Upgrade and Migration > Check product and patch installation status, or run (Get-SPFarm).BuildVersion in SharePoint Management Shell. Builds below 16.0.20326.20278 are affected.

## Fix

Install KB5002945 (November 10, 2026 public update), build 16.0.20326.20278 or later, on SharePoint Server Subscription Edition.

## Timeline

- 2026-11-10T19:24:25+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-109499
- 2026-11-11T00:41:56+00:00 analyst https://nvd.nist.gov/vuln/detail/CVE-2026-109499 — KB5002945 (Microsoft) lists CVE-2026-109499 and build 16.0.20326.20278; affected range from Microsoft CNA record via NVD. MSRC page unreadable, so only fix verified. No exploitation or PoC reported; not in KEV. Microsoft rates it Important (CVSS 8.8).

## Documents

- [advisory] NVD CVE-2026-109499 (Microsoft CNA record) https://nvd.nist.gov/vuln/detail/CVE-2026-109499
- [describes] SharePoint security fixes released with November 2026 PU https://blog.stefan-gossner.com/2026/11/10/sharepoint-security-fixes-released-with-november-2026-pu-and-offered-through-microsoft-update/
- [fix] KB5002945: SharePoint Server Subscription Edition security update, November 10, 2026 https://support.microsoft.com/en-us/servicing/office/hotfix/sharepoint/5002945

## From the sources

Access of resource using incompatible type ('type confusion') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

---

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