ASP.NET Core Denial of Service Vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2020-1161: 5.31% estimated exploitation activity in the next 30 days; percentile 92.61 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

A denial of service vulnerability exists when ASP.NET Core improperly handles web requests, aka 'ASP.NET Core Denial of Service Vulnerability'.

Published by the source

24 May 2022, 17:18 UTC

Last modified by the source

2 Feb 2023, 05:08 UTC

Source last checked

26 Oct 2026, 16:59 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3cf7-7wq6-8842

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# Patch Next advisory brief: CVE-2020-1161

Advisory: ASP.NET Core Denial of Service Vulnerability
IDs: CVE-2020-1161, GHSA-3cf7-7wq6-8842
Record: https://patchnext.com/advisories/cve-2020-1161 (revision 1, source checked 26 Oct 2026, 16:59 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: microsoft.aspnetcore.app.runtime.linux-arm64 3.1.4; microsoft.aspnetcore.app.runtime.linux-musl-arm64 3.1.4; microsoft.aspnetcore.app.runtime.osx-x64 3.1.4; microsoft.aspnetcore.app.runtime.linux-arm 3.1.4; microsoft.aspnetcore.app.runtime.win-x86 3.1.4; microsoft.aspnetcore.app.runtime.linux-x64 3.1.4; microsoft.aspnetcore.app.runtime.win-arm 3.1.4; microsoft.aspnetcore.app.runtime.linux-musl-x64 3.1.4; microsoft.aspnetcore.app.runtime.win-x64 3.1.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet microsoft.aspnetcore.app.runtime.linux-arm64: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.linux-musl-arm64: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.osx-x64: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.linux-arm: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.win-x86: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.linux-x64: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.win-arm: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.linux-musl-x64: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4
- NuGet microsoft.aspnetcore.app.runtime.win-x64: affected >= 3.1.0, < 3.1.4; fixed in 3.1.4

## Suggested inspection (read-only)
- NuGet microsoft.aspnetcore.app.runtime.linux-arm64: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.linux-musl-arm64: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.osx-x64: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.linux-arm: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.win-x86: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.linux-x64: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.win-arm: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.linux-musl-x64: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.app.runtime.win-x64: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on microsoft.aspnetcore.app.runtime.linux-arm64, microsoft.aspnetcore.app.runtime.linux-musl-arm64, microsoft.aspnetcore.app.runtime.osx-x64, microsoft.aspnetcore.app.runtime.linux-arm, microsoft.aspnetcore.app.runtime.win-x86, microsoft.aspnetcore.app.runtime.linux-x64, microsoft.aspnetcore.app.runtime.win-arm, microsoft.aspnetcore.app.runtime.linux-musl-x64, microsoft.aspnetcore.app.runtime.win-x64.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3cf7-7wq6-8842 (GitHub-reviewed advisory GHSA-3cf7-7wq6-8842 lists affected ranges: NuGet microsoft.aspnetcore.app.runtime.linux-arm >=3.1.0 =3.1.0 =3.1.0 =3.1.0 =3.1.0 =3.1.0 <3.1.4; NuGet…)

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