---
id: CVE-2026-45659
title: >-
  Deserialization of untrusted data in Microsoft Office SharePoint allows an
  authorized attacker to execute code over a network.
summary: >-
  Deserialization of untrusted data in Microsoft Office SharePoint allows an
  authorized attacker to execute code over a network.
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-502
vendor: microsoft
product: sharepoint_server
affected:
  - sharepoint_server < 16.0.19725.20280
  - sharepoint_server = 2016
  - sharepoint_server = 2019
patched:
  - sharepoint_server 16.0.19725.20280
published: '2026-05-22'
updated: '2026-07-02'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45659'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659'
    label: secure@microsoft.com
  - url: >-
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45659
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - kev
  - in-the-wild
  - exploit-available
epss: 0.02704
epssPercentile: 0.85326
kev: true
kevDateAdded: '2026-07-01'
kevDueDate: '2026-07-04'
kevRansomware: true
exploited: true
ingestedAt: '2026-07-02T05:23:56.583Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/HORKimhab/CVE-2026-45659'
  checkedAt: '2026-09-25T08:20:58.250Z'
exploitAvailable: true
---

## Overview

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

## Affected

- `sharepoint_server < 16.0.19725.20280`
- `sharepoint_server = 2016`
- `sharepoint_server = 2019`

## Remediation

Upgrade past the affected range:

- `sharepoint_server 16.0.19725.20280`