CVE-2025-55248 — Microsoft.NetCore.App.Run…
MEDIUMCVE-2025-55248 is a medium-severity (CVSS 5.7) CWE-326 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-2025-55248: .NET Information Disclosure Vulnerability
Exploitation Status
No confirmed exploitation observed yet
- 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-2025-55248.
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-2025-55248 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+16 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
Inadequate encryption strength in .NET, .NET Framework, Visual Studio allows an authorized attacker to disclose information over a network.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-arm | ≥ 9.0.0&&< 9.0.10 | 9.0.10dotnet add package Microsoft.NetCore.App.Runtime.linux-arm --version 9.0.10 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-arm64 | ≥ 9.0.0&&< 9.0.10 | 9.0.10dotnet add package Microsoft.NetCore.App.Runtime.linux-arm64 --version 9.0.10 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-musl-arm | ≥ 9.0.0&&< 9.0.10 | 9.0.10dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm --version 9.0.10 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-musl-arm64 | ≥ 9.0.0&&< 9.0.10 | 9.0.10dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm64 --version 9.0.10 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-musl-x64 | ≥ 9.0.0&&< 9.0.10 | 9.0.10dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-x64 --version 9.0.10 |
| .NETNuGet | Microsoft.NetCore.App.Runtime.linux-x64 | ≥ 9.0.0&&< 9.0.10 | 9.0.10dotnet add package Microsoft.NetCore.App.Runtime.linux-x64 --version 9.0.10 |
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 9.0.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55248 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-2025-55248 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-55248. 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.
The Red Hat Product Security team has assessed the severity of this vulnerability as High, given that it can be remotely exploited by a man-in-the-middle attacker without authentication or user interaction. Successful exploitation allows an attacker to disable TLS protection between a .NET client and an SMTP server,…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | dotnet8.0-0:8.0.121-1.el10_0 | RHSA-2025:18152 |
| Red Hat Enterprise Linux 10 | dotnet9.0-0:9.0.111-1.el10_0 | RHSA-2025:18153 |
| Red Hat Enterprise Linux 8 | dotnet8.0-0:8.0.121-1.el8_10 | RHSA-2025:18148 |
| Red Hat Enterprise Linux 8 | dotnet9.0-0:9.0.111-1.el8_10 | RHSA-2025:18150 |
| Red Hat Enterprise Linux 9 | dotnet8.0-0:8.0.121-1.el9_6 | RHSA-2025:18149 |
| Red Hat Enterprise Linux 9 | dotnet9.0-0:9.0.111-1.el9_6 | RHSA-2025:18151 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | dotnet8.0-0:8.0.121-1.el9_4 | RHSA-2025:18256 |
| Red Hat Hardened Images | dotnet8-0-main-8.0.126-1.hum1 | RHSA-2026:9080 |
Frequently Asked Questions
Is CVE-2025-55248 in your dependencies?
O3 Security finds CVE-2025-55248 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.