Denial of service in ASP.NET Core

Exploitation

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

CVSS

7.5 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2017-11883: 8.53% estimated exploitation activity in the next 30 days; percentile 95.06 (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.

.NET Core 1.0, 1.1, and 2.0 allow an unauthenticated attacker to remotely cause a denial of service attack against a .NET Core web application by improperly handling web requests, aka ".NET CORE Denial Of Service Vulnerability".

Published by the source

13 May 2022, 01:42 UTC

Last modified by the source

27 Jan 2023, 05:02 UTC

Source last checked

26 Oct 2026, 16:58 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-f9jc-rrm2-pmfg

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# Patch Next advisory brief: CVE-2017-11883

Advisory: Denial of service in ASP.NET Core
IDs: CVE-2017-11883, GHSA-f9jc-rrm2-pmfg
Record: https://patchnext.com/advisories/cve-2017-11883 (revision 1, source checked 26 Oct 2026, 16:58 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.server.httpsys 2.0.2; microsoft.net.http.server 1.1.4, 1.0.6; microsoft.aspnetcore.server.weblistener 1.1.4, 1.0.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet microsoft.aspnetcore.server.httpsys: affected >= 2.0.0, < 2.0.2; fixed in 2.0.2
- NuGet microsoft.net.http.server: affected >= 1.0.0, < 1.0.6; >= 1.1.0, < 1.1.4; fixed in 1.1.4, 1.0.6
- NuGet microsoft.aspnetcore.server.weblistener: affected >= 1.0.0, < 1.0.6; >= 1.1.0, < 1.1.4; fixed in 1.1.4, 1.0.6

## Suggested inspection (read-only)
- NuGet microsoft.aspnetcore.server.httpsys: check the installed version with your package manager.
- NuGet microsoft.net.http.server: check the installed version with your package manager.
- NuGet microsoft.aspnetcore.server.weblistener: 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.server.httpsys, microsoft.net.http.server, microsoft.aspnetcore.server.weblistener.
- 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-f9jc-rrm2-pmfg (GitHub-reviewed advisory GHSA-f9jc-rrm2-pmfg lists affected ranges: NuGet microsoft.aspnetcore.server.weblistener >=1.0.0 =1.1.0 =1.0.0 =1.1.0 =2.0.0 <2.0.2)

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