# CVE-2023-38171: Microsoft QUIC Denial of Service Vulnerability

> Attackers can cause a denial of service in Microsoft QUIC implementations via a null pointer dereference, affecting Windows and .NET environments.

- **Severity:** High 7.5 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Oct 2023
- **Updated:** 14 Apr 2025
- **Also known as:** BIT-dotnet-2023-38171, BIT-dotnet-sdk-2023-38171, GHSA-xh5m-8qqp-c5x7

## What is CVE-2023-38171?

CVE-2023-38171 is a high-severity vulnerability in Microsoft .Net, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Microsoft QUIC Denial of Service Vulnerability

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-38171?

6 open source packages ship an affected version, including Microsoft.Native.Quic.MsQuic.OpenSSL, dotnet and dotnet-sdk. It affects 4 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.Native.Quic.MsQuic.OpenSSL` | NuGet | All versions | 2.2.3 |
| `Microsoft.Native.Quic.MsQuic.OpenSSL` | NuGet | All versions | 2.2.3 |
| `dotnet` | Bitnami | From 7.0.0 | 7.0.12 |
| `dotnet-sdk` | Bitnami | From 7.0.0 | 7.0.12 |
| `Microsoft.Native.Quic.MsQuic.Schannel` | NuGet | All versions | 2.2.3 |
| `Microsoft.Native.Quic.MsQuic.Schannel` | NuGet | All versions | 2.2.3 |

Products: Microsoft .Net, Microsoft Visual Studio 2022, Microsoft Windows 11 22h2, Microsoft Windows Server 2022.

## How do I fix CVE-2023-38171?

Upgrade Microsoft.Native.Quic.MsQuic.OpenSSL to 2.2.3 or later.

## Is CVE-2023-38171 being exploited?

There is no known exploitation of CVE-2023-38171 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft .Net

- [CVE-2024-43498](https://insights.sbomify.com/CVE-2024-43498/): .NET and Visual Studio Remote Code Execution Vulnerability (critical 9.8)
- [CVE-2024-0057](https://insights.sbomify.com/CVE-2024-0057/): NET, .NET Framework, and Visual Studio Security Feature Bypass Vulnerability (critical 9.1)
- [CVE-2026-96957](https://insights.sbomify.com/CVE-2026-96957/): .NET Security Feature Bypass Vulnerability (high 8.8)
- [CVE-2026-69439](https://insights.sbomify.com/CVE-2026-69439/): .NET and Visual Studio Elevation of Privilege Vulnerability (high 8.8)
- [CVE-2026-71328](https://insights.sbomify.com/CVE-2026-71328/): .NET and Visual Studio Remote Code Execution Vulnerability (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-38171 and fix it if it is affected.

What it is: CVE-2023-38171 is a high-severity vulnerability in Microsoft .Net, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-38171 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.Native.Quic.MsQuic.OpenSSL (NuGet): affected all versions; fixed in 2.2.3
- Microsoft.Native.Quic.MsQuic.OpenSSL (NuGet): affected all versions; fixed in 2.2.3
- dotnet (Bitnami): affected from 7.0.0; fixed in 7.0.12
- dotnet-sdk (Bitnami): affected from 7.0.0; fixed in 7.0.12
- Microsoft.Native.Quic.MsQuic.Schannel (NuGet): affected all versions; fixed in 2.2.3
- Microsoft.Native.Quic.MsQuic.Schannel (NuGet): affected all versions; fixed in 2.2.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-38171/ (Markdown: https://insights.sbomify.com/CVE-2023-38171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-38171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-38171
- OSV: https://osv.dev/vulnerability/CVE-2023-38171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-38171/
Summaries are generated and may contain mistakes; the official description above is the record.