---
id: CVE-2026-62899
title: .NET Security Feature Bypass Vulnerability
summary: >-
  Inconsistent interpretation of http requests ('http request/response
  smuggling') in .NET allows an unauthorized attacker to bypass a security
  feature over a network.
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C'
cvssSource: cna
cwe:
  - CWE-444
vendor: Microsoft
product: .NET 10.0
affected:
  - .net_10.0 >= 10.0.0 < 10.0.11
  - .net_8.0 >= 8.0.0 < 8.0.30
  - .net_9.0 >= 9.0.0 < 9.0.19
  - visual_studio_2022_version_17.14 >= 17.14.0 < 17.14.38
  - visual_studio_2026_version_18.8 >= 18.0 < 18.8.3
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-12T13:48:04.279657Z'
published: '2026-08-11'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T16:24:08.049Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-62899'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62899'
    label: .NET Security Feature Bypass Vulnerability
  - url: 'https://github.com/dotnet/runtime/security/advisories/GHSA-r6mh-95jw-g7qg'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-62899'
  - url: 'https://github.com/dotnet/announcements/issues/427'
  - url: 'https://github.com/advisories/GHSA-r6mh-95jw-g7qg'
tags:
  - cve.org
  - ghsa
  - nuget
epss: 0.00706
epssPercentile: 0.51974
aliases:
  - GHSA-r6mh-95jw-g7qg
ecosystem: nuget
patched:
  - Microsoft.NETCore.App.Runtime.linux-arm 10.0.11
  - Microsoft.NETCore.App.Runtime.linux-arm64 10.0.11
  - Microsoft.NETCore.App.Runtime.linux-musl-arm 10.0.11
  - Microsoft.NETCore.App.Runtime.linux-musl-arm64 10.0.11
  - Microsoft.NETCore.App.Runtime.linux-musl-x64 10.0.11
  - Microsoft.NETCore.App.Runtime.linux-x64 10.0.11
  - Microsoft.NETCore.App.Runtime.osx-arm64 10.0.11
  - Microsoft.NETCore.App.Runtime.osx-x64 10.0.11
  - Microsoft.NETCore.App.Runtime.linux-arm 9.0.19
  - Microsoft.NETCore.App.Runtime.linux-arm64 9.0.19
  - Microsoft.NETCore.App.Runtime.linux-musl-arm 9.0.19
  - Microsoft.NETCore.App.Runtime.linux-musl-arm64 9.0.19
  - Microsoft.NETCore.App.Runtime.linux-musl-x64 9.0.19
  - Microsoft.NETCore.App.Runtime.linux-x64 9.0.19
  - Microsoft.NETCore.App.Runtime.osx-arm64 9.0.19
  - Microsoft.NETCore.App.Runtime.osx-x64 9.0.19
  - Microsoft.NETCore.App.Runtime.linux-arm 8.0.30
  - Microsoft.NETCore.App.Runtime.linux-arm64 8.0.30
  - Microsoft.NETCore.App.Runtime.linux-musl-arm 8.0.30
  - Microsoft.NETCore.App.Runtime.linux-musl-arm64 8.0.30
  - Microsoft.NETCore.App.Runtime.linux-musl-x64 8.0.30
  - Microsoft.NETCore.App.Runtime.linux-x64 8.0.30
  - Microsoft.NETCore.App.Runtime.osx-arm64 8.0.30
  - Microsoft.NETCore.App.Runtime.osx-x64 8.0.30
ingestedAt: '2026-08-11T18:47:43.145Z'
---

## Overview

Inconsistent interpretation of http requests ('http request/response smuggling') in .NET allows an unauthorized attacker to bypass a security feature over a network.

## Affected

- `.net_10.0 >= 10.0.0 < 10.0.11`
- `.net_8.0 >= 8.0.0 < 8.0.30`
- `.net_9.0 >= 9.0.0 < 9.0.19`
- `visual_studio_2022_version_17.14 >= 17.14.0 < 17.14.38`
- `visual_studio_2026_version_18.8 >= 18.0 < 18.8.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-62899)

Affected packages:

- `Microsoft.NETCore.App.Runtime.linux-arm >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.linux-arm64 >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm64 >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.linux-musl-x64 >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.linux-x64 >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.osx-arm64 >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.osx-x64 >= 10.0.0, <= 10.0.10`
- `Microsoft.NETCore.App.Runtime.linux-arm >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.linux-arm64 >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm64 >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.linux-musl-x64 >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.linux-x64 >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.osx-arm64 >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.osx-x64 >= 9.0.0, <= 9.0.18`
- `Microsoft.NETCore.App.Runtime.linux-arm >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.linux-arm64 >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm64 >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.linux-musl-x64 >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.linux-x64 >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.osx-arm64 >= 8.0.0, <= 8.0.29`
- `Microsoft.NETCore.App.Runtime.osx-x64 >= 8.0.0, <= 8.0.29`

Patched in:

- `Microsoft.NETCore.App.Runtime.linux-arm 10.0.11`
- `Microsoft.NETCore.App.Runtime.linux-arm64 10.0.11`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm 10.0.11`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm64 10.0.11`
- `Microsoft.NETCore.App.Runtime.linux-musl-x64 10.0.11`
- `Microsoft.NETCore.App.Runtime.linux-x64 10.0.11`
- `Microsoft.NETCore.App.Runtime.osx-arm64 10.0.11`
- `Microsoft.NETCore.App.Runtime.osx-x64 10.0.11`
- `Microsoft.NETCore.App.Runtime.linux-arm 9.0.19`
- `Microsoft.NETCore.App.Runtime.linux-arm64 9.0.19`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm 9.0.19`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm64 9.0.19`
- `Microsoft.NETCore.App.Runtime.linux-musl-x64 9.0.19`
- `Microsoft.NETCore.App.Runtime.linux-x64 9.0.19`
- `Microsoft.NETCore.App.Runtime.osx-arm64 9.0.19`
- `Microsoft.NETCore.App.Runtime.osx-x64 9.0.19`
- `Microsoft.NETCore.App.Runtime.linux-arm 8.0.30`
- `Microsoft.NETCore.App.Runtime.linux-arm64 8.0.30`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm 8.0.30`
- `Microsoft.NETCore.App.Runtime.linux-musl-arm64 8.0.30`
- `Microsoft.NETCore.App.Runtime.linux-musl-x64 8.0.30`
- `Microsoft.NETCore.App.Runtime.linux-x64 8.0.30`
- `Microsoft.NETCore.App.Runtime.osx-arm64 8.0.30`
- `Microsoft.NETCore.App.Runtime.osx-x64 8.0.30`

Source: https://github.com/advisories/GHSA-r6mh-95jw-g7qg