---
id: "CVE-2026-85790"
kind: "vulnerability"
aliases: ["CVE-2026-85790", "GHSA-2mxg-prvg-9jfg"]
title: "Microsoft Security Advisory CVE-2026-85790 - .NET Information Disclosure Vulnerability"
severity: "medium"
cvss: 5.900000095367432
epss: 0.006899999920278788
exploited: false
status: "open"
category: "package"
products: [{"name": "Microsoft.Native.Quic.MsQuic.Schannel", "fixed": ["2.5.12"], "affected": ">= 1.9.0, < 2.5.12", "ecosystem": "nuget"}, {"name": "Microsoft.Native.Quic.MsQuic.Schannel", "fixed": ["2.6.3"], "affected": ">= 2.6.0, < 2.6.3", "ecosystem": "nuget"}, {"name": "microsoft windows 11 23h2", "fixed": ["10.0.22631.7652"], "affected": "< 10.0.22631.7652", "ecosystem": "vendor"}, {"name": "microsoft windows 11 24h2", "fixed": ["10.0.26100.9711"], "affected": "< 10.0.26100.9711", "ecosystem": "vendor"}, {"name": "microsoft windows 11 25h2", "fixed": ["10.0.26200.9711"], "affected": "< 10.0.26200.9711", "ecosystem": "vendor"}, {"name": "microsoft windows 11 26h1", "fixed": ["10.0.28000.3231"], "affected": "< 10.0.28000.3231", "ecosystem": "vendor"}, {"name": "microsoft windows 11 26h2", "fixed": ["10.0.26300.9711"], "affected": "< 10.0.26300.9711", "ecosystem": "vendor"}, {"name": "microsoft windows server 2022", "fixed": ["10.0.20348.5761"], "affected": "< 10.0.20348.5761", "ecosystem": "vendor"}, {"name": "microsoft windows server 2025", "fixed": ["10.0.26100.33650"], "affected": "< 10.0.26100.33650", "ecosystem": "vendor"}, {"name": "microsoft native.quic.msquic.schannel", "fixed": ["2.6.2"], "affected": "< 2.6.2", "ecosystem": "vendor"}, {"name": "microsoft visual studio 2022", "fixed": ["17.14.42"], "affected": ">= 17.14.0, < 17.14.42", "ecosystem": "vendor"}, {"name": "microsoft visual studio 2026", "fixed": ["18.10.4"], "affected": ">= 18.10.0, < 18.10.4", "ecosystem": "vendor"}]
ecosystems: ["nuget", "vendor"]
tags: ["cwe-416", "dotnet", "nuget", "package", "quic", "self-contained-apps", "windows"]
not_affected_if: ["linux-only", "macos-only", "package-version-outside-affected-ranges"]
published_at: "2026-10-13T19:21:02+00:00"
first_seen_at: "2026-10-23T19:11:32+00:00"
updated_at: "2026-10-23T23:44:52+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-2mxg-prvg-9jfg", "first_seen_at": "2026-10-23T19:11:32+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85790", "first_seen_at": "2026-10-23T23:44:52+00:00"}]
---

# Microsoft Security Advisory CVE-2026-85790 - .NET Information Disclosure Vulnerability

A use-after-free flaw (CWE-416) in the NuGet package Microsoft.Native.Quic.MsQuic.Schannel, which ships MsQuic for .NET on Windows, has a CVSS 3.1 score of 5.9 with high confidentiality impact. The advisory text says an attacker may read information from memory, with no authentication needed, but the sources do not describe the exact trigger.

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

## Affected

- nuget:Microsoft.Native.Quic.MsQuic.Schannel affected >= 1.9.0, < 2.5.12 fixed 2.5.12
- nuget:Microsoft.Native.Quic.MsQuic.Schannel affected >= 2.6.0, < 2.6.3 fixed 2.6.3
- vendor:microsoft windows 11 23h2 affected < 10.0.22631.7652 fixed 10.0.22631.7652
- vendor:microsoft windows 11 24h2 affected < 10.0.26100.9711 fixed 10.0.26100.9711
- vendor:microsoft windows 11 25h2 affected < 10.0.26200.9711 fixed 10.0.26200.9711
- vendor:microsoft windows 11 26h1 affected < 10.0.28000.3231 fixed 10.0.28000.3231
- vendor:microsoft windows 11 26h2 affected < 10.0.26300.9711 fixed 10.0.26300.9711
- vendor:microsoft windows server 2022 affected < 10.0.20348.5761 fixed 10.0.20348.5761
- vendor:microsoft windows server 2025 affected < 10.0.26100.33650 fixed 10.0.26100.33650
- vendor:microsoft native.quic.msquic.schannel affected < 2.6.2 fixed 2.6.2
- vendor:microsoft visual studio 2022 affected >= 17.14.0, < 17.14.42 fixed 17.14.42
- vendor:microsoft visual studio 2026 affected >= 18.10.0, < 18.10.4 fixed 18.10.4

## How to check

Run dotnet --info and check whether the .NET SDK or runtime is older than the patched release.
Search project files and lockfiles for Microsoft.Native.Quic.MsQuic.Schannel and compare the version to the affected ranges (>= 1.9.0 < 2.5.12, or >= 2.6.0 < 2.6.3).
For self-contained apps, check the version they were published with, since they bundle their own copy.

## Fix

Update the package reference to 2.5.12 (for the 2.5 line) or 2.6.3 (for the 2.6 line), then rebuild.
Install the latest .NET release, restart apps, and recompile and redeploy self-contained apps built against an affected version.

## Timeline

- 2026-10-23T19:11:32+00:00 ghsa https://github.com/advisories/GHSA-2mxg-prvg-9jfg
- 2026-10-23T23:44:52+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-85790

## From the sources

## Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.Native.Quic.MsQuic.Schannel. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Various vulnerabilities in MsQuic are addressed by an updated native-binary dependency update.

## Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/470

## CVSS Details

- **Version:** 3.1
- **Severity:** Moderate
- **Score:** 5.9
- **Vector:** `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`

- **Weakness:** CWE-416 (Use After Free)
## Affected Platforms

- **Platforms:** Windows
- **Architectures:** All

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

The vulnerability affects Microsoft .NET projects that use an affected package version listed below.

Package name | Affected version | Patched version
------------ | ---------------- | ---------------
[Microsoft.Native.Quic.MsQuic.Schannel](https://www.nuget.org/packages/Microsoft.Native.Quic.MsQuic.Schannel) | >= 1.9.0, < 2.5.12 | 2.5.12
[Microsoft.Native.Quic.MsQuic.Schannel](https://www.nuget.org/packages/Microsoft.Native.Quic.MsQuic.Schannel) | >= 2.6.0, < 2.6.3 | 2.6.3

## Advisory FAQ

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

If using a package listed in [affected packages](#affected-packages), you're exposed to the vulnerability.

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

1. To fix the issue please install the latest version of .NET. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the `dotnet --info` command.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed [self-contained applications](https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd) targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.

## 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-2026-85790](https://www.cve.org/CVERecord?id=CVE-2026-85790)

### Acknowledgements

- reinusKR

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_