---
id: CVE-2026-102866
title: >-
  Improper verification of cryptographic signature in Microsoft Office
  SharePoint allows an unauthorized attacker to elevate privileges over a
  network.
summary: >-
  Improper verification of cryptographic signature in Microsoft Office
  SharePoint allows an unauthorized attacker to elevate privileges over a
  network.
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-347
vendor: microsoft
product: sharepoint_server
affected:
  - sharepoint_server < 16.0.20326.20190
patched:
  - sharepoint_server 16.0.20326.20190
published: '2026-10-13'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T19:45:04.610'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102866'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102866'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
epss: 0.00666
epssPercentile: 0.51623
ingestedAt: '2026-10-13T19:43:28.899Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-13T21:14:01.595856Z'
---

## Overview

Improper verification of cryptographic signature in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.

## Affected

- `sharepoint_server < 16.0.20326.20190`

## Remediation

Upgrade past the affected range:

- `sharepoint_server 16.0.20326.20190`