CVE-2020-1161Network attack vector

Unauthenticated remote service interruption

Published May 21, 2020 · Updated Aug 19, 2026

Denial of service in ASP.NET Core 3.1.3 and earlier allows remote attackers to interrupt web applications via crafted requests. Microsoft has not published the affected request-processing locus or the incorrect operation performed on attacker-controlled request data. No authentication or user interaction is required; successful exploitation interrupts only the targeted ASP.NET Core web application.

CVSS severity7.5
High
EPSS probability5.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in ASP.NET Core 3.1.3 and earlier allows remote attackers to interrupt web applications via crafted requests. Microsoft has not published the affected request-processing locus or the incorrect operation performed on attacker-controlled request data. No authentication or user interaction is required; successful exploitation interrupts only the targeted ASP.NET Core web application.

The record

CVE
CVE-2020-1161
Published
May 21, 2020
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Microsoft Visual Studio 2019
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=16.0 <publication

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Visual Studio 2019version=16.0 <publication
Microsoft · ASP.NET Coreversion=3.0 <publication
Microsoft · Microsoft Visual Studio 2017version=15.9.0 <publication

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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