---
id: CVE-2020-1123
title: >-
  A denial of service vulnerability exists when Connected User Experiences and
  Telemetry Service improperly handles file operations
summary: >-
  A denial of service vulnerability exists when Connected User Experiences and
  Telemetry Service improperly handles file operations. An attacker who
  successfully exploited this vulnerability could cause a system to stop
  responding.

  To expl…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: microsoft
product: windows_10
affected:
  - windows_10
  - windows_10 = 1607
  - windows_10 = 1709
  - windows_10 = 1803
  - windows_10 = 1809
  - windows_10 = 1903
  - windows_10 = 1909
  - windows_server_2016
  - windows_server_2019
published: '2020-05-21'
updated: '2026-08-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-1123'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1123'
    label: secure@microsoft.com
  - url: >-
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1123
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01086
epssPercentile: 0.63837
ingestedAt: '2026-08-19T17:42:38.651Z'
---

## Overview

A denial of service vulnerability exists when Connected User Experiences and Telemetry Service improperly handles file operations. An attacker who successfully exploited this vulnerability could cause a system to stop responding.
To exploit the vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability.
The security update addresses the vulnerability by  correcting how the Connected User Experiences and Telemetry Service handles file operations.

## Affected

- `windows_10`
- `windows_10 = 1607`
- `windows_10 = 1709`
- `windows_10 = 1803`
- `windows_10 = 1809`
- `windows_10 = 1903`
- `windows_10 = 1909`
- `windows_server_2016`
- `windows_server_2019`

## Remediation

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