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.NET
.NET NuGet
Not in CISA KEV
HIGH severity

Remote Denial of Service Vulnerability in Microsoft.Native.Quic.MsQuic.SchannelGHSA-xh5m-8qqp-c5x7

HIGHFix: microsoft/msquic@3226cff

GHSA-xh5m-8qqp-c5x7 is a high-severity (CVSS 7.5) NULL Pointer Dereference vulnerability in Microsoft.Native.Quic.MsQuic.Schannel. EPSS puts its 30-day exploitation probability at 71.0% (99th percentile). A fix is available for Microsoft.Native.Quic.MsQuic.Schannel — see the affected versions and patch details below.

Also known asBIT-dotnet-2023-38171BIT-dotnet-sdk-2023-38171CVE-2023-38171
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-xh5m-8qqp-c5x7.

EPSS Exploitation Probability

via FIRST.org ↗
71.0%probability of exploitation in next 30 days
Very High Risk0.00%
Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk
0.00%30.0%59.9%89.9%9.0%71.0%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected
.NETMicrosoft.Native.Quic.MsQuic.Schannel.NETMicrosoft.Native.Quic.MsQuic.OpenSSL

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The MsQuic server application or process will crash, resulting in a denial of service.

Patches

The following patch was made:

Workarounds

Beyond upgrading to the patched versions, there is no other workaround. You must upgrade or disable MsQuic functionality.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetMicrosoft.Native.Quic.MsQuic.Schannelall versions2.2.3dotnet add package Microsoft.Native.Quic.MsQuic.Schannel --version 2.2.3
.NETNuGetMicrosoft.Native.Quic.MsQuic.OpenSSLall versions2.2.3dotnet add package Microsoft.Native.Quic.MsQuic.OpenSSL --version 2.2.3

Affected Products

4 products · 7 configurations
Application
.netmicrosoft
≥ 7.0.0 && < 7.0.12
range
Application
visual studio 2022microsoft
≥ 17.7.0 && < 17.7.5
range
OS
windows 11 22h2microsoft
< 10.0.22621.2428
range
OS
windows server 2022microsoft
all

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.Native.Quic.MsQuic.Schannel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update Microsoft.Native.Quic.MsQuic.Schannel to 2.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xh5m-8qqp-c5x7 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact The MsQuic server application or process will crash, resulting in a denial of service. ### Patches The following patch was made: - Don't Allow Version Negotiation Packets for Server Connections - https://github.com/microsoft/msquic/commit/3226cff07d22662f16fc98d605656860e64cd343 ### Workarounds Beyond upgrading to the patched versions, there is no other workaround. You must upgrade or disable MsQuic functionality.
O3 Security · Impact-Aware SCA

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Remote Denial of Service Vulnerability in Microsoft.Native.…