# CVE-2021-26423: .NET Core Elevation of Privilege Vulnerability

Source: https://junglewise.ai/threats/cve-2021-26423-net-core-elevation-of-privilege-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-10-25  
License: CC BY 4.0 with a link back

CVE-2021-26423 · Severity: low · CVSS 3.1 · Published 2022-10-25

.NET Core Elevation of Privilege Vulnerability

Technologies: [Microsoft.NetCore.App.Runtime.linux-arm (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-linux-arm), [Microsoft.NetCore.App.Runtime.linux-arm64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-linux-arm64), [Microsoft.NetCore.App.Runtime.linux-musl-arm (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-linux-musl-arm), [Microsoft.NetCore.App.Runtime.linux-musl-arm64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-linux-musl-arm64), [Microsoft.NetCore.App.Runtime.linux-musl-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-linux-musl-x64), [Microsoft.NetCore.App.Runtime.linux-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-linux-x64), [Microsoft.NETCore.App.Runtime.Mono.linux-arm (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-linux-arm), [Microsoft.NETCore.App.Runtime.Mono.linux-arm64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-linux-arm64), [Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-linux-musl-x64), [Microsoft.NETCore.App.Runtime.Mono.linux-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-linux-x64), [Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-llvm-aot-linux-arm64), [Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-llvm-aot-linux-x64), [Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-llvm-aot-osx-x64), [Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-llvm-linux-arm64), [Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-llvm-linux-x64), [Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-llvm-osx-x64), [Microsoft.NETCore.App.Runtime.Mono.osx-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-mono-osx-x64), [Microsoft.NetCore.App.Runtime.osx-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-osx-x64), [Microsoft.NETCore.App.Runtime.rhel.6-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-rhel-6-x64), [Microsoft.NetCore.App.Runtime.win-arm (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-win-arm), [Microsoft.NetCore.App.Runtime.win-arm64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-win-arm64), [Microsoft.NetCore.App.Runtime.win-x64 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-win-x64), [Microsoft.NetCore.App.Runtime.win-x86 (NuGet)](https://junglewise.ai/threats/technologies/microsoft-netcore-app-runtime-win-x86). Vendors: [NuGet](https://junglewise.ai/threats/vendors/nuget).

## Quick answers

**Is CVE-2021-26423 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-26423 being exploited in the wild.

**How severe is CVE-2021-26423?** Low severity, with a CVSS score of 3.1, published 25 October 2022.

**Which products and versions are affected?** Microsoft.NetCore.App.Runtime.linux-arm (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18; Microsoft.NetCore.App.Runtime.linux-arm64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18; Microsoft.NetCore.App.Runtime.linux-musl-arm (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9; Microsoft.NetCore.App.Runtime.linux-musl-arm64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18; and 19 more.

**Is there a fix for CVE-2021-26423?** Yes. Microsoft.NetCore.App.Runtime.linux-arm (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.linux-arm64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.linux-musl-arm (NuGet): upgrade to 5.0.9 or later; Microsoft.NetCore.App.Runtime.linux-musl-arm64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.linux-musl-x64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.linux-x64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NETCore.App.Runtime.Mono.linux-arm (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.linux-arm64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.linux-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NETCore.App.Runtime.Mono.osx-x64 (NuGet): upgrade to 5.0.9 or later; Microsoft.NetCore.App.Runtime.osx-x64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NETCore.App.Runtime.rhel.6-x64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.win-arm (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.win-arm64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.win-x64 (NuGet): upgrade to 3.1.18 or later; Microsoft.NetCore.App.Runtime.win-x86 (NuGet): upgrade to 3.1.18 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-26423?** Check whether you run Microsoft.NetCore.App.Runtime.linux-arm (NuGet), Microsoft.NetCore.App.Runtime.linux-arm64 (NuGet), Microsoft.NetCore.App.Runtime.linux-musl-arm (NuGet) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Microsoft.NetCore.App.Runtime.linux-arm (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.linux-arm --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.linux-arm64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.linux-arm64 --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.linux-musl-arm (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm --version 5.0.9
  ```

- Microsoft.NetCore.App.Runtime.linux-musl-arm64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-arm64 --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.linux-musl-x64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.linux-musl-x64 --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.linux-x64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.linux-x64 --version 3.1.18
  ```

- Microsoft.NETCore.App.Runtime.Mono.linux-arm (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.linux-arm --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.linux-arm64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.linux-arm64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.linux-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.linux-x64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 --version 5.0.9
  ```

- Microsoft.NETCore.App.Runtime.Mono.osx-x64 (NuGet): upgrade to 5.0.9 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.Mono.osx-x64 --version 5.0.9
  ```

- Microsoft.NetCore.App.Runtime.osx-x64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.osx-x64 --version 3.1.18
  ```

- Microsoft.NETCore.App.Runtime.rhel.6-x64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NETCore.App.Runtime.rhel.6-x64 --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.win-arm (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.win-arm --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.win-arm64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.win-arm64 --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.win-x64 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.win-x64 --version 3.1.18
  ```

- Microsoft.NetCore.App.Runtime.win-x86 (NuGet): upgrade to 3.1.18 or later

  ```sh
  dotnet add package Microsoft.NetCore.App.Runtime.win-x86 --version 3.1.18
  ```


## Affected products

- Microsoft.NetCore.App.Runtime.linux-arm (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.linux-arm64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.linux-musl-arm (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NetCore.App.Runtime.linux-musl-arm64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.linux-musl-x64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.linux-x64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NETCore.App.Runtime.Mono.linux-arm (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.linux-arm64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.linux-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NETCore.App.Runtime.Mono.osx-x64 (NuGet) ECOSYSTEM:introduced=5.0.0,fixed=5.0.9
- Microsoft.NetCore.App.Runtime.osx-x64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NETCore.App.Runtime.rhel.6-x64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.win-arm (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.win-arm64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.win-x64 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18
- Microsoft.NetCore.App.Runtime.win-x86 (NuGet) ECOSYSTEM:introduced=3.1.0,fixed=3.1.18

## Identifiers

- CVE-2021-26423
- GHSA-rh58-r7jh-xhx3

## Related threats

- [.NET Core Runtime link following privilege escalation on Unix](https://junglewise.ai/threats/cve-2026-96225-microsoft-security-advisory-net-and-visual-studio-elevation-of)
- [.NET Runtime symlink following elevation of privilege](https://junglewise.ai/threats/cve-2026-96231-microsoft-security-advisory-net-and-visual-studio-elevation-of)
- [.NET System.Net.Sockets out-of-bounds write in IPv4/IPv6 datagram handling](https://junglewise.ai/threats/cve-2026-70197-microsoft-security-advisory-net-and-visual-studio-remote-code)
- [.NET System.Runtime DateTime parsing out-of-bounds read](https://junglewise.ai/threats/cve-2026-96233-microsoft-security-advisory-net-and-visual-studio-denial-of)
- [.NET TLS client certificate verification bypass](https://junglewise.ai/threats/cve-2026-70194-microsoft-security-advisory-net-and-visual-studio-security)