CVE-2026-118749: ASP.NET Core inefficient algorithmic complexity denial of service

CVE-2026-118749 · Severity: high · CVSS 7.5 · Published 2026-11-10

ASP.NET Core is a web application framework used to build cloud services and web applications. An attacker can send specially crafted network requests that exploit inefficient algorithmic complexity in the framework, causing the server to consume excessive resources and become unavailable to legitimate users.

Technologies: Microsoft Asp.Net Core, Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet), Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet), Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet), Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet), Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet), Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet), Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet), Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet), Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet), Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet), Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet). Vendors: Microsoft, NuGet.

Quick answers

Is CVE-2026-118749 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-118749 being exploited in the wild.
How severe is CVE-2026-118749?
High severity, with a CVSS score of 7.5, published 10 November 2026.
Which products and versions are affected?
Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet) >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148, ECOSYSTEM:introduced=11.0.0-rc.1.26425.128,fixed=11.0.0; Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet) >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148, ECOSYSTEM:introduced=11.0.0-rc.1.26425.128,fixed=11.0.0; Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet) >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148, ECOSYSTEM:introduced=11.0.0-rc.1.26425.128,fixed=11.0.0; Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet) >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148, ECOSYSTEM:introduced=11.0.0-rc.1.26425.128,fixed=11.0.0; and 8 more.
Is there a fix for CVE-2026-118749?
Yes. Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet): upgrade to 11.0.0 or later; Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet): upgrade to 11.0.0 or later; Microsoft.Extensions.Validation (NuGet): upgrade to 11.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-118749 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-118749?
Check whether you run Microsoft Asp.Net Core, Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet), Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.linux-arm --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.linux-arm64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-arm --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-x64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.linux-x64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.osx-arm64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.osx-x64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.win-arm64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.win-x64 --version 11.0.0
  • Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.AspNetCore.App.Runtime.win-x86 --version 11.0.0
  • Microsoft.Extensions.Validation (NuGet): upgrade to 11.0.0 or later
    dotnet add package Microsoft.Extensions.Validation --version 11.0.0

Technical details

An inefficient algorithmic complexity vulnerability in ASP.NET Core allows an unauthenticated, network-based attacker to trigger a denial of service condition by exploiting poorly optimized processing logic. The vulnerability requires no authentication or user interaction and can be exploited remotely, resulting in service unavailability.

Affected products

  • Microsoft ASP.NET Core

Identifiers

  • CVE-2026-118749
  • GHSA-m28h-pj36-4364

Timeline

  • 2026-11-10: disclosed

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.