---
id: CVE-2025-64394
title: >-
  A vulnerability allowing a low-privileged local user to write arbitrary files
  with SYSTEM privileges during the installation of Veeam Backup for Microsoft
  365, which can lead to privilege escalation or denial of service.
summary: >-
  A vulnerability allowing a low-privileged local user to write arbitrary files
  with SYSTEM privileges during the installation of Veeam Backup for Microsoft
  365, which can lead to privilege escalation or denial of service.
severity: medium
cvss: 4.3
cvssVector: 'CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-1386
vendor: Veeam
product: Backup for Microsoft 365
affected:
  - backup_for_microsoft_365 >= 8.0 <= 8.6.0.1102
published: '2026-10-27'
updated: '2026-10-27'
sourceUpdated: '2026-10-27T16:16:58.979Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-64394'
references:
  - url: 'https://www.veeam.com/kb4957'
tags:
  - cve.org
ingestedAt: '2026-10-27T16:32:34.386Z'
---

## Overview

A vulnerability allowing a low-privileged local user to write arbitrary files with SYSTEM privileges during the installation of Veeam Backup for Microsoft 365, which can lead to privilege escalation or denial of service.

## Affected

- `backup_for_microsoft_365 >= 8.0 <= 8.6.0.1102`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.