GHSA-c494-m2fq-59mx — Microsoft.NETCore.App.Run…
HIGHGHSA-c494-m2fq-59mx is a high-severity (CVSS 7.5) Use After Free vulnerability in Microsoft.NETCore.App.Runtime.win-arm64. A fix is available for Microsoft.NETCore.App.Runtime.win-arm64 — see the affected versions and patch details below.
Microsoft Security Advisory CVE-2026-62898 – .NET Information Disclosure Vulnerability
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-c494-m2fq-59mx.
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-c494-m2fq-59mx plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
Microsoft.NETCore.App.Runtime.win-arm64.NETMicrosoft.NETCore.App.Runtime.win-x64.NETMicrosoft.NETCore.App.Runtime.win-x86.NETMicrosoft.NETCore.App.Runtime.win-arm64.NETMicrosoft.NETCore.App.Runtime.win-x64.NETMicrosoft.NETCore.App.Runtime.win-x86.NETMicrosoft.NETCore.App.Runtime.win-arm64.NETMicrosoft.NETCore.App.Runtime.win-x64+1 moreReal-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
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft QUIC. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
A use after free in Microsoft QUIC allows an unauthorized attacker to disclose information over a network.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/426
CVSS Details
- Version: 3.1
- Severity: High
- Score: 7.5
- Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C - Weakness: CWE-416: Use After Free
Affected Platforms
- Platforms: Windows
- Architectures: All
<a name="affected-packages"></a>Affected Packages
The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below
<a name=".NET 10"></a>.NET 10
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.NETCore.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.10 | 10.0.11 |
| Microsoft.NETCore.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.10 | 10.0.11 |
| Microsoft.NETCore.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.10 | 10.0.11 |
<a name=".NET 9"></a>.NET 9
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.NETCore.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.18 | 9.0.19 |
| Microsoft.NETCore.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.18 | 9.0.19 |
| Microsoft.NETCore.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.18 | 9.0.19 |
<a name=".NET 8"></a>.NET 8
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.NETCore.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.29 | 8.0.30 |
| Microsoft.NETCore.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.29 | 8.0.30 |
| Microsoft.NETCore.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.29 | 8.0.30 |
Advisory FAQ
<a name="how-affected"></a>How do I know if I am affected?
If using a package listed in affected packages, an application is exposed to the vulnerability.
<a name="how-fix"></a>How do I fix the issue?
- To fix the issue please install the latest version of .NET. If an application has installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt a user to update Visual Studio, which will also update their .NET SDKs.
- If an application references the vulnerable package, update the package reference to the patched version. Users can list the versions they have installed by running the
dotnet --infocommand.
Once users have installed the updated runtime or SDK, they need to restart their apps for the update to take effect.
Additionally, if users have deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.
Other Information
Reporting Security Issues
If users 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. Further information can be found in the MSRC Report an Issue FAQ.
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
Users 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. Users 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
Revisions
V1.0 (08/11/2026): Advisory published.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.NETCore.App.Runtime.win-arm64 | ≥ 10.0.0&&< 10.0.11 | 10.0.11dotnet add package Microsoft.NETCore.App.Runtime.win-arm64 --version 10.0.11 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.win-x64 | ≥ 10.0.0&&< 10.0.11 | 10.0.11dotnet add package Microsoft.NETCore.App.Runtime.win-x64 --version 10.0.11 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.win-x86 | ≥ 10.0.0&&< 10.0.11 | 10.0.11dotnet add package Microsoft.NETCore.App.Runtime.win-x86 --version 10.0.11 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.win-arm64 | ≥ 9.0.0&&< 9.0.19 | 9.0.19dotnet add package Microsoft.NETCore.App.Runtime.win-arm64 --version 9.0.19 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.win-x64 | ≥ 9.0.0&&< 9.0.19 | 9.0.19dotnet add package Microsoft.NETCore.App.Runtime.win-x64 --version 9.0.19 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.win-x86 | ≥ 9.0.0&&< 9.0.19 | 9.0.19dotnet add package Microsoft.NETCore.App.Runtime.win-x86 --version 9.0.19 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.NETCore.App.Runtime.win-arm64, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.NETCore.App.Runtime.win-arm64 to 10.0.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c494-m2fq-59mx 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-c494-m2fq-59mx can be triaged on real exposure rather than presence alone.
Tailored to GHSA-c494-m2fq-59mx. 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-c494-m2fq-59mx in your dependencies?
O3 Security finds GHSA-c494-m2fq-59mx across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.