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 69.7% (99th percentile). A fix is available for Microsoft.Native.Quic.MsQuic.Schannel — see the affected versions and patch details below.
Remote Denial of Service Vulnerability in Microsoft.Native.Quic.MsQuic.Schannel
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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-xh5m-8qqp-c5x7 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
Microsoft.Native.Quic.MsQuic.Schannel.NETMicrosoft.Native.Quic.MsQuic.OpenSSLReal-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:
- 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.Native.Quic.MsQuic.Schannel | all versions | 2.2.3dotnet add package Microsoft.Native.Quic.MsQuic.Schannel --version 2.2.3 |
| .NETNuGet | Microsoft.Native.Quic.MsQuic.OpenSSL | all versions | 2.2.3dotnet add package Microsoft.Native.Quic.MsQuic.OpenSSL --version 2.2.3 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-xh5m-8qqp-c5x7 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-xh5m-8qqp-c5x7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-xh5m-8qqp-c5x7 in your dependencies?
O3 Security finds GHSA-xh5m-8qqp-c5x7 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.