Moderate severity vulnerability that affects Microsoft.AspNetCore.All, Microsoft.AspNetCore.App, and Microsoft.AspNetCore.Server.Kestrel.Core
What to do
Vendor fix available. Upgrade each affected package to the fixed version on its release line (microsoft.aspnetcore.all 2.1.2, 2.0.9; microsoft.aspnetcore.server.kestrel.core 2.1.2, 2.0.4; microsoft.aspnetcore.app 2.1.2), redeploy, then verify what is actually installed.
This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.
Affected packages
NuGet microsoft.aspnetcore.all
- Affected
- >= 2.0.0, < 2.0.9>= 2.1.0, < 2.1.2
- Fixed in
- 2.0.9, 2.1.2
NuGet microsoft.aspnetcore.server.kestrel.core
- Affected
- >= 2.0.0, < 2.0.4>= 2.1.0, < 2.1.2
- Fixed in
- 2.1.2, 2.0.4
NuGet microsoft.aspnetcore.app
- Affected
- >= 2.1.0, < 2.1.2
- Fixed in
- 2.1.2
Sources
- GitHub Advisory Database and maintainer security advisories on GitHub
GitHub-reviewed advisory GHSA-cgpw-2gph-2r9g lists affected ranges: NuGet microsoft.aspnetcore.server.kestrel.core >=2.0.0 =2.1.0 =2.0.0 =2.1.0 =2.1.0 <2.1.2
VerifiedObserved Structured GitHub Advisory Database record (type=reviewed) from the GitHub REST API.
Severity and exploitation
- Exploitation
- No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
- CVSS
- not scored
- EPSS
- No dated EPSS signal available.
Source description
As published by the source; long descriptions are shortened.
Microsoft is aware of a denial of service vulnerability in ASP.NET Core when a malformed request is terminated. An attacker who successfully exploited this vulnerability could cause a denial of service attack. The update addresses the vulnerability by correcting how ASP.NET Core handles such requests.
Dates and revisions
- Published by the source
- Last modified by the source
- Source last checked
- Revision 1 · created ·
Published from ghsa record GHSA-cgpw-2gph-2r9g
Agent brief
Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.
# Patch Next advisory brief: GHSA-cgpw-2gph-2r9g Advisory: Moderate severity vulnerability that affects Microsoft.AspNetCore.All, Microsoft.AspNetCore.App, and Microsoft.AspNetCore.Server.Kestrel.Core IDs: GHSA-cgpw-2gph-2r9g Record: https://patchnext.com/advisories/ghsa-cgpw-2gph-2r9g (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: Unrated Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV. Vendor response: Vendor fix available; fixed versions by package: microsoft.aspnetcore.all 2.1.2, 2.0.9; microsoft.aspnetcore.server.kestrel.core 2.1.2, 2.0.4; microsoft.aspnetcore.app 2.1.2. A vendor fix does not mean a deployment is fixed. ## Affected components - NuGet microsoft.aspnetcore.all: affected >= 2.0.0, < 2.0.9; >= 2.1.0, < 2.1.2; fixed in 2.0.9, 2.1.2 - NuGet microsoft.aspnetcore.server.kestrel.core: affected >= 2.0.0, < 2.0.4; >= 2.1.0, < 2.1.2; fixed in 2.1.2, 2.0.4 - NuGet microsoft.aspnetcore.app: affected >= 2.1.0, < 2.1.2; fixed in 2.1.2 ## Suggested inspection (read-only) - NuGet microsoft.aspnetcore.all: check the installed version with your package manager. - NuGet microsoft.aspnetcore.server.kestrel.core: check the installed version with your package manager. - NuGet microsoft.aspnetcore.app: 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.all, microsoft.aspnetcore.server.kestrel.core, microsoft.aspnetcore.app. - 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-cgpw-2gph-2r9g (GitHub-reviewed advisory GHSA-cgpw-2gph-2r9g lists affected ranges: NuGet microsoft.aspnetcore.server.kestrel.core >=2.0.0 =2.1.0 =2.0.0 =2.1.0 =2.1.0 <2.1.2) Commands are suggestions: review each one before running it.
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