---
id: "CVE-2026-118748"
page: "https://infrastack.ai/live/CVE-2026-118748"
kind: "vulnerability"
aliases: ["CVE-2026-118748", "GHSA-5h82-77p6-2wp3"]
title: "Microsoft Security Advisory CVE-2026-118748 - ASP.NET Core Denial of Service Vulnerability"
severity: "high"
cvss: 7.5
epss: null
exploited: false
status: "open"
category: "runtime"
products: [{"name": "ASP.NET Core", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.1, < 11.0.0", "ecosystem": "nuget"}, {"name": "Visual Studio 2026", "fixed": ["18.12.0"], "affected": "< 18.12.0", "ecosystem": "vendor"}, {"name": "Microsoft.AspNetCore.App.Runtime.linux-arm", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.linux-arm64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.linux-musl-arm", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.linux-musl-arm64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.linux-musl-x64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.linux-x64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.osx-arm64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.osx-x64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.win-arm64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.win-x64", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}, {"name": "Microsoft.AspNetCore.App.Runtime.win-x86", "fixed": ["11.0.0"], "affected": ">= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148", "ecosystem": "nuget"}]
ecosystems: ["nuget", "vendor"]
tags: [".net", "aspnet-core", "blazor", "cwe-770", "dotnet-11", "runtime", "web-api"]
not_affected_if: ["dotnet-10-or-earlier", "no-blazor-static-ssr"]
published_at: "2026-11-10T19:19:51+00:00"
first_seen_at: "2026-11-10T19:24:55+00:00"
updated_at: "2026-11-11T00:15:14+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118748", "first_seen_at": "2026-11-10T19:24:55+00:00"}, {"source": "analyst", "url": "https://devblogs.microsoft.com/dotnet/dotnet-and-dotnet-framework-november-2026-servicing-updates/", "first_seen_at": "2026-11-10T22:59:39+00:00", "cites": ["https://devblogs.microsoft.com/dotnet/dotnet-and-dotnet-framework-november-2026-servicing-updates/", "https://app.opencve.io/cve/CVE-2026-118748"]}, {"source": "ghsa", "url": "https://github.com/advisories/GHSA-5h82-77p6-2wp3", "first_seen_at": "2026-11-11T00:14:38+00:00"}]
exploit_sources: []
---

# Microsoft Security Advisory CVE-2026-118748 - ASP.NET Core Denial of Service Vulnerability

Link for people: https://infrastack.ai/live/CVE-2026-118748 (this .md is for agents)

Blazor static server-side rendering validation keeps attacker-controlled field names in an unbounded singleton cache. A remote attacker can make the process consume memory until it fails, causing denial of service.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- nuget:ASP.NET Core affected >= 11.0.0-preview.1, < 11.0.0 fixed 11.0.0
- vendor:Visual Studio 2026 affected < 18.12.0 fixed 18.12.0
- nuget:Microsoft.AspNetCore.App.Runtime.linux-arm affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.linux-arm64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.linux-musl-arm affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.linux-musl-x64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.linux-x64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.osx-arm64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.osx-x64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.win-arm64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.win-x64 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0
- nuget:Microsoft.AspNetCore.App.Runtime.win-x86 affected >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 fixed 11.0.0

## How to check

- Check the ASP.NET Core runtime version with `dotnet --list-runtimes` and look for Microsoft.AspNetCore.App 11.0.0 or later.
- Check application package references for Microsoft.AspNetCore.App.Runtime.* at a version from `11.0.0-preview.7.26381.103` up to `11.0.0-rc.3.26522.148`.
- Check whether the app uses Blazor static server-side rendering with forms validation.
- Check Visual Studio 2026 is below `18.12.0`.

## Fix

- ASP.NET Core and Microsoft.AspNetCore.App.Runtime packages: `11.0.0`
- Visual Studio 2026: `18.12.0`

## Timeline

- 2026-11-10T19:24:55+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118748
- 2026-11-10T22:59:39+00:00 analyst https://devblogs.microsoft.com/dotnet/dotnet-and-dotnet-framework-november-2026-servicing-updates/ — Microsoft .NET Nov 2026 servicing blog lists CVE for .NET 11 only; versions/fix from CVE record mirror (OpenCVE); MSRC page unreadable, so nothing marked verified. No config condition stated; no exploitation or PoC seen.
- 2026-11-11T00:14:38+00:00 ghsa https://github.com/advisories/GHSA-5h82-77p6-2wp3

## Documents

- [advisory] .NET and .NET Framework November 2026 servicing updates https://devblogs.microsoft.com/dotnet/dotnet-and-dotnet-framework-november-2026-servicing-updates/
- [advisory] Maintainer's advisory: api.github.com https://api.github.com/repos/dotnet/aspnetcore/security-advisories/GHSA-5h82-77p6-2wp3
- [advisory] Maintainer's advisory: github.com https://github.com/dotnet/aspnetcore/security/advisories/GHSA-5h82-77p6-2wp3
- [describes] CVE-2026-118748 - OpenCVE (CVE record mirror) https://app.opencve.io/cve/CVE-2026-118748
- [fix] Release: github.com https://github.com/dotnet/aspnetcore/releases/tag/v11.0.0

## From the sources

## Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

Blazor static-SSR client validation retains attacker-controlled rendered field names in an unbounded singleton cache, allowing remote process memory exhaustion.

## Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/516

## CVSS Details

- **Version:** 3.1
- **Severity:** High
- **Score:** 7.5 (base score)
- **Vector:** `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C`
- **Weakness:** CWE-770

## Affected Platforms

- **Platforms:** Windows, Linux, macOS
- **Architectures:** All

## <a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

### .NET 11.0 - affected runtime packages

Package | Affected version | Patched version
--- | --- | ---
[Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-x64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-arm64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-x64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x64) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0
[Microsoft.AspNetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x86) | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0

## Advisory FAQ

### <a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

### <a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

## Other Information

### Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the [MSRC Researcher Portal](https://msrc.microsoft.com/report/vulnerability/new). Further information can be found in the MSRC [Report an Issue FAQ](https://www.microsoft.com/msrc/faqs-report-an-issue).

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

### Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

### Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

### External Links

[CVE-2026-118748](https://www.cve.org/CVERecord?id=CVE-2026-118748)

### Acknowledgements

- Artur Stetsko
- Alejandro Pacheco

### Revisions

V1.0 (November 10, 2026): Advisory published.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_