CVE-2025-21172 — Microsoft.NetCore.App.Run…
HIGHCVE-2025-21172 is a high-severity (CVSS 7.5) CWE-122 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-2025-21172 | .NET and Visual Studio Remote Code Execution Vulnerability
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 CVE-2025-21172.
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
CVE-2025-21172 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 377,166 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.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+15 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
.NET and Visual Studio Remote Code Execution Vulnerability
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-arm | ≥ 9.0.0&&< 9.0.1 | 9.0.1dotnet add package Microsoft.NetCore.App.Runtime.linux-arm --version 9.0.1 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-arm64 | ≥ 9.0.0&&< 9.0.1 | 9.0.1dotnet add package Microsoft.NetCore.App.Runtime.linux-arm64 --version 9.0.1 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-musl-arm | ≥ 9.0.0&&< 9.0.1 | 9.0.1dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm --version 9.0.1 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-musl-arm64 | ≥ 9.0.0&&< 9.0.1 | 9.0.1dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm64 --version 9.0.1 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-musl-x64 | ≥ 9.0.0&&< 9.0.1 | 9.0.1dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-x64 --version 9.0.1 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-x64 | ≥ 9.0.0&&< 9.0.1 | 9.0.1dotnet add package Microsoft.NetCore.App.Runtime.linux-x64 --version 9.0.1 |
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.linux-arm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.NetCore.App.Runtime.linux-arm to 9.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-21172 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 CVE-2025-21172 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-21172. 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.
This issue affects .NET Framework as shipped with all versions of RHEL. However, this flaw is not known to be exploitable under any supported scenario. ``` .NET 6.0 for RHEL-8, RHEL-9 and RHIVOS has reached its End of Life as of November 12, 2024, and is no longer supported. No fixes will be provided for this stream.…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | dotnet8.0-0:8.0.112-1.el8_10 | RHSA-2025:0381 |
| Red Hat Enterprise Linux 8 | dotnet9.0-0:9.0.102-1.el8_10 | RHSA-2025:0382 |
| Red Hat Enterprise Linux 9 | dotnet8.0-0:8.0.112-1.el9_5 | RHBA-2025:0304 |
| Red Hat Enterprise Linux 9 | dotnet9.0-0:9.0.102-1.el9_5 | RHBA-2025:0305 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | dotnet8.0-0:8.0.112-1.el9_4 | RHSA-2025:0532 |
Frequently Asked Questions
Is CVE-2025-21172 in your dependencies?
O3 Security finds CVE-2025-21172 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.