CVE-2026-70183 — Microsoft.AspNetCore.App.…
HIGHCVE-2026-70183 is a high-severity (CVSS 7.5) CWE-362 vulnerability in Microsoft.AspNetCore.App.Runtime.linux-arm. A fix is available for Microsoft.AspNetCore.App.Runtime.linux-arm — see the affected versions and patch details below.
Microsoft Security Advisory CVE-2026-70183 - ASP.NET Core Security Feature Bypass 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-2026-70183.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-70183 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
Microsoft.AspNetCore.App.Runtime.linux-arm.NETMicrosoft.AspNetCore.App.Runtime.linux-arm64.NETMicrosoft.AspNetCore.App.Runtime.linux-musl-arm.NETMicrosoft.AspNetCore.App.Runtime.linux-musl-arm64.NETMicrosoft.AspNetCore.App.Runtime.linux-musl-x64.NETMicrosoft.AspNetCore.App.Runtime.linux-x64.NETMicrosoft.AspNetCore.App.Runtime.osx-arm64.NETMicrosoft.AspNetCore.App.Runtime.osx-x64+40 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.AspNetCore.Components.Authorization. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
A stale asynchronous authorization result in Blazor AuthorizeRouteView can be applied after navigation or an authorization-state change, bypassing the current [Authorize] decision.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/460
CVSS Details
- Version: 3.1
- Severity: High
- Score: 7.5
- Vector:
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'))
Affected Platforms
- Platforms: Windows, Linux, macOS
- Architectures: All
<a name="affected-packages"></a>Affected Packages
The vulnerability affects Microsoft .NET projects that use an affected package version listed below.
Advisory FAQ
<a name="how-affected"></a>How do I know if I am affected?
If using a package listed in affected packages, you're 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 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.
- 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 --infocommand.
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 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
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
Acknowledgements
- l8BL with ENKI WhiteHat (https://enki.co.kr/)
Revisions
V1.0 (10/13/2026): Advisory published.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-arm | ≥ 8.0.0&&< 8.0.32 | 8.0.32dotnet add package Microsoft.AspNetCore.App.Runtime.linux-arm --version 8.0.32 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-arm64 | ≥ 8.0.0&&< 8.0.32 | 8.0.32dotnet add package Microsoft.AspNetCore.App.Runtime.linux-arm64 --version 8.0.32 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-musl-arm | ≥ 8.0.0&&< 8.0.32 | 8.0.32dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-arm --version 8.0.32 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | ≥ 8.0.0&&< 8.0.32 | 8.0.32dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 --version 8.0.32 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | ≥ 8.0.0&&< 8.0.32 | 8.0.32dotnet add package Microsoft.AspNetCore.App.Runtime.linux-musl-x64 --version 8.0.32 |
| .NETNuGet | Microsoft.AspNetCore.App.Runtime.linux-x64 | ≥ 8.0.0&&< 8.0.32 | 8.0.32dotnet add package Microsoft.AspNetCore.App.Runtime.linux-x64 --version 8.0.32 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.AspNetCore.App.Runtime.linux-arm, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Microsoft.AspNetCore.App.Runtime.linux-arm to 8.0.32 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-70183 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.
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.
An elevation of privilege flaw, rated IMPORTANT by Red Hat Product Security, was found in the Blazor AuthorizeRouteView component of ASP.NET Core. Due to improper synchronization of concurrent execution using a shared resource (a race condition), a stale asynchronous authorization result can be applied after…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. The upstream advisory states that the issue is fixed in ASP.NET Core Runtime 8.0.32, 9.0.21, and 10.0.13 (and 11.0.0-rc.2 for the .NET 11 pre-release channel); users should apply the patched versions of the affected .NET components for their Red Hat offerings once available.Source: Red Hat security advisory for CVE-2026-70183 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | dotnet8.0-0:8.0.132-1.el10_2 | RHSA-2026:86168 |
| Red Hat Enterprise Linux 10 | dotnet9.0-0:9.0.122-1.el10_2 | RHSA-2026:86172 |
| Red Hat Enterprise Linux 10 | dotnet10.0-0:10.0.113-1.el10_2 | RHSA-2026:86195 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | dotnet9.0-0:9.0.122-1.el10_0 | RHSA-2026:88424 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | dotnet8.0-0:8.0.132-1.el10_0 | RHSA-2026:88474 |
| Red Hat Enterprise Linux 8 | dotnet9.0-0:9.0.122-1.el8_10 | RHSA-2026:86170 |
| Red Hat Enterprise Linux 8 | dotnet10.0-0:10.0.113-1.el8_10 | RHSA-2026:86192 |
| Red Hat Enterprise Linux 8 | dotnet8.0-0:8.0.132-2.el8_10 | RHSA-2026:86594 |
Frequently Asked Questions
Is CVE-2026-70183 in your dependencies?
Find it across NuGet, including transitive dependencies.