---
id: CVE-2020-1161
title: >-
  A denial of service vulnerability exists when ASP.NET Core improperly handles
  web requests
summary: >-
  A denial of service vulnerability exists when ASP.NET Core improperly handles
  web requests. An attacker who successfully exploited this vulnerability could
  cause a denial of service against an ASP.NET Core web application. The
  vulnerabil…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: microsoft
product: asp.net_core
affected:
  - asp.net_core = 3.1
  - 'visual_studio_2017 >= 15.1, <= 15.9'
  - 'visual_studio_2019 >= 16.0, <= 16.5'
published: '2020-05-21'
updated: '2026-08-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-1161'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1161'
    label: secure@microsoft.com
  - url: >-
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1161
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.05142
epssPercentile: 0.92103
ingestedAt: '2026-08-19T17:42:39.840Z'
---

## Overview

A denial of service vulnerability exists when ASP.NET Core improperly handles web requests. An attacker who successfully exploited this vulnerability could cause a denial of service against an ASP.NET Core web application. The vulnerability can be exploited remotely, without authentication.
A remote unauthenticated attacker could exploit this vulnerability by issuing specially crafted requests to the ASP.NET Core application.
The update addresses the vulnerability by correcting how the ASP.NET Core web application handles web requests.

## Affected

- `asp.net_core = 3.1`
- `visual_studio_2017 >= 15.1, <= 15.9`
- `visual_studio_2019 >= 16.0, <= 16.5`

## Remediation

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