CVE-2020-1123 Connected User Experiences and Telemetry Service Denial of Service Vulnerability

Medium 5.5 Published 21 May 2020 Updated 19 Aug 2026

A local attacker can cause a system hang by exploiting improper file handling in the Connected User Experiences and Telemetry Service.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2020-1123?

CVE-2020-1123 is a medium-severity denial of service vulnerability in Microsoft Windows 10, published on 21 May 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Which versions are affected by CVE-2020-1123?

It affects 3 products.

Products include Microsoft Windows 10, Microsoft Windows Server 2016, Microsoft Windows Server 2019.

How do I fix CVE-2020-1123?

No fix has been published for CVE-2020-1123 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-1123 being exploited?

There is no known exploitation of CVE-2020-1123 in the wild and no public exploit code.

All Microsoft Windows 10 vulnerabilities

Sources

Also known as GHSA-cwpm-73h2-wvf2.