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HIGH severity

GHSA-266m-wp2v-x7mq Microsoft.NetCore.App.Run…

HIGH

GHSA-266m-wp2v-x7mq is a high-severity (CVSS 7.5) CWE-426 vulnerability in Microsoft.NetCore.App.Runtime.linux-arm. A fix is available for Microsoft.NetCore.App.Runtime.linux-arm — see the affected versions and patch details below.

Microsoft Security Advisory CVE-2025-30399 | .NET Remote Code Vulnerability

Also known asBIT-dotnet-2025-30399BIT-dotnet-sdk-2025-30399BIT-powershell-2025-30399CVE-2025-30399
Published
Jun 11, 2025
Updated
Sep 10, 2026
Affected
24 pkgs
Patched
24 / 24
Exploits
None indexed
Exploitation data as of Sep 17, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • 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-266m-wp2v-x7mq.

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk

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-266m-wp2v-x7mq 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 376,715 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

24 pkgs affected
.NETMicrosoft.NetCore.App.Runtime.linux-arm.NETMicrosoft.NetCore.App.Runtime.linux-arm64.NETMicrosoft.NetCore.App.Runtime.linux-musl-arm.NETMicrosoft.NetCore.App.Runtime.linux-musl-arm64.NETMicrosoft.NetCore.App.Runtime.linux-musl-x64.NETMicrosoft.NetCore.App.Runtime.linux-x64.NETMicrosoft.NetCore.App.Runtime.osx-arm64.NETMicrosoft.NetCore.App.Runtime.osx-x64+16 more

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

Microsoft Security Advisory CVE-2025-30399 | .NET Remote Code Vulnerability

<a name="executive-summary"></a>Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0 and .NET 9.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

An attacker could exploit this vulnerability by placing files in particular locations, leading to unintended code execution.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/362

<a name="mitigation-factors"></a>Mitigation factors

Microsoft has not identified any mitigating factors for this vulnerability.

<a name="affected-software"></a>Affected software

  • Any .NET 8.0 application running on .NET 8.0.16 or earlier.
  • Any .NET 9.0 application running on .NET 9.0.5 or earlier.

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

The vulnerability affects any Microsoft .NET project if it uses any of affected packages versions listed below

<a name=".NET 9"></a>.NET 9

<a name=".NET 8"></a>.NET 8

Package nameAffected versionPatched version
Microsoft.NetCore.App.Runtime.linux-arm>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.linux-arm64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.linux-musl-arm>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.linux-musl-arm64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.linux-musl-x64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.linux-x64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.osx-arm64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.osx-x64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.win-arm>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.win-arm64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.win-x64>= 8.0.0, <= 8.0.168.0.17
Microsoft.NetCore.App.Runtime.win-x86>= 8.0.0, <= 8.0.168.0.17

Advisory FAQ

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

If you have a runtime with a version listed, or an affected package listed in affected software or 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 9.0 or .NET 8.0, as appropriate. 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. You will see output like the following;
.NET SDK:
 Version:           9.0.100
 Commit:            59db016f11
 Workload version:  9.0.100-manifests.3068a692
 MSBuild version:   17.12.7+5b8665660

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  15.2
 OS Platform: Darwin
 RID:         osx-arm64
 Base Path:   /usr/local/share/dotnet/sdk/9.0.100/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
  Version:      9.0.0
  Architecture: arm64
  Commit:       9d5a6a9aa4

.NET SDKs installed:
  9.0.100 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 9.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 9.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  x64   [/usr/local/share/dotnet]
    registered at [/etc/dotnet/install_location_x64]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

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 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 .NET 9.0 or .NET 8.0, please email details to [email protected]. Reports may qualify for the Microsoft .NET Core & .NET 5 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-2025-30399

Revisions

V1.0 (June 10, 2025): Advisory published.

Affected Packages

24 total 24 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetMicrosoft.NetCore.App.Runtime.linux-arm9.0.0&&< 9.0.69.0.6dotnet add package Microsoft.NetCore.App.Runtime.linux-arm --version 9.0.6
.NETNuGetMicrosoft.NetCore.App.Runtime.linux-arm649.0.0&&< 9.0.69.0.6dotnet add package Microsoft.NetCore.App.Runtime.linux-arm64 --version 9.0.6
.NETNuGetMicrosoft.NetCore.App.Runtime.linux-musl-arm9.0.0&&< 9.0.69.0.6dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm --version 9.0.6
.NETNuGetMicrosoft.NetCore.App.Runtime.linux-musl-arm649.0.0&&< 9.0.69.0.6dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm64 --version 9.0.6
.NETNuGetMicrosoft.NetCore.App.Runtime.linux-musl-x649.0.0&&< 9.0.69.0.6dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-x64 --version 9.0.6
.NETNuGetMicrosoft.NetCore.App.Runtime.linux-x649.0.0&&< 9.0.69.0.6dotnet add package Microsoft.NetCore.App.Runtime.linux-x64 --version 9.0.6

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.NetCore.App.Runtime.linux-arm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update Microsoft.NetCore.App.Runtime.linux-arm to 9.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-266m-wp2v-x7mq is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-266m-wp2v-x7mq can be triaged on real exposure rather than presence alone.

Tailored to GHSA-266m-wp2v-x7mq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This vulnerability is Important because it allows remote code execution at the runtime level, targeting the fundamental assembly loading mechanism of .NET. Unlike moderate flaws that may require complex chaining or rely on user interaction, this issue can be exploited simply by placing malicious files in specific…

ProductFixed inAdvisory
Red Hat Enterprise Linux 10dotnet8.0-0:8.0.117-1.el10_0RHSA-2025:8814
Red Hat Enterprise Linux 10dotnet9.0-0:9.0.107-1.el10_0RHSA-2025:8816
Red Hat Enterprise Linux 8dotnet8.0-0:8.0.117-1.el8_10RHSA-2025:8812
Red Hat Enterprise Linux 8dotnet9.0-0:9.0.107-1.el8_10RHSA-2025:8815
Red Hat Enterprise Linux 9dotnet8.0-0:8.0.117-1.el9_6RHSA-2025:8813
Red Hat Enterprise Linux 9dotnet9.0-0:9.0.107-1.el9_6RHSA-2025:8817
Red Hat Enterprise Linux 9.4 Extended Update Supportdotnet8.0-0:8.0.117-1.el9_4RHSA-2025:9066

Frequently Asked Questions

# Microsoft Security Advisory CVE-2025-30399 | .NET Remote Code Vulnerability ## <a name="executive-summary"></a>Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0 and .NET 9.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. An attacker could exploit this vulnerability by placing files in particular locations, leading to unintended code execution. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/
O3 Security · Impact-Aware SCA

Is GHSA-266m-wp2v-x7mq in your dependencies?

O3 Security finds GHSA-266m-wp2v-x7mq across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-266m-wp2v-x7mq: High 7.5 severity | O3 Security