6.5
Medium
Microsoft.NETCore.App

CVE-2021-1721

CVE-2021-1721 is a medium-severity security vulnerability in Microsoft.NETCore.App (nuget), affecting versions >= 2.1.0, < 2.1.25. It is fixed in 2.1.25, 3.1.12, 5.0.3.

Key facts
◎
CVSS score
6.5
Medium
↗
Attack vector
Network
☷
Issuing authority
GitHub Advisory Database
□
Affected package
Microsoft.NETCore.App
✓
Fixed in
2.1.25, 3.1.12, 5.0.3
☼
Disclosed
2021

Summary

.NET Core and Visual Studio Denial of Service Vulnerability due to a vulnerability which exists when creating HTTPS web request during X509 certificate chain building.

Impact

Severity and exposure

CVE-2021-1721 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.

A fixed version is available (2.1.25, 3.1.12, 5.0.3). Upgrading removes the vulnerable code path.

Affected versions

nuget

  • Microsoft.NETCore.App (>= 2.1.0, < 2.1.25)
  • Microsoft.NETCore.App.Host.linux-arm (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-arm64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-musl-arm64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-musl-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.osx-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.rhel.6-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-arm (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-arm64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-x86 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-arm (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-arm64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-musl-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.osx-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.rhel.6-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-arm (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-arm64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-x64 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-x86 (>= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-arm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.osx-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-arm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-x86 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.browser-wasm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.ios-arm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.ios-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.ios-x86 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-arm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-musl-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.osx-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.tvos-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.tvos-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.win-arm (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.win-arm64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.win-x64 (>= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.win-x86 (>= 5.0.0, < 5.0.3)

Security releases

  • Microsoft.NETCore.App → 2.1.25 (nuget)
  • Microsoft.NETCore.App.Host.linux-arm → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.linux-arm64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.linux-musl-arm64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.linux-musl-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.linux-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.osx-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.rhel.6-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.win-arm → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.win-arm64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.win-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Host.win-x86 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-arm → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-arm64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-musl-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.osx-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.rhel.6-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.win-arm → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.win-arm64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.win-x64 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.win-x86 → 3.1.12 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.linux-arm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.linux-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.linux-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.Mono.osx-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.android-arm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.android-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.android-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.android-x86 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.browser-wasm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.ios-arm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.ios-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.ios-x86 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-arm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-musl-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.linux-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.osx-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.tvos-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.tvos-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.win-arm → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.win-arm64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.win-x64 → 5.0.3 (nuget)
  • Microsoft.NETCore.App.Runtime.win-x86 → 5.0.3 (nuget)
Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.

Kodem's runtime-powered SCA identifies whether CVE-2021-1721 is reachable in your applications. Explore open-source security for your team.

See if CVE-2021-1721 is reachable in your applications. Get a demo

Remediation advice

Upgrade the following packages to resolve this vulnerability:

  • Upgrade Microsoft.NETCore.App to 2.1.25 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-musl-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-musl-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.osx-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.rhel.6-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-x86 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.osx-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.rhel.6-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x86 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-x86 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.browser-wasm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.ios-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.ios-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.ios-x86 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.tvos-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.tvos-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x86 to 5.0.3 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently asked questions about CVE-2021-1721

What is CVE-2021-1721?

CVE-2021-1721 is a medium-severity security vulnerability in Microsoft.NETCore.App (nuget), affecting versions >= 2.1.0, < 2.1.25. It is fixed in 2.1.25, 3.1.12, 5.0.3.

How severe is CVE-2021-1721?

CVE-2021-1721 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which packages are affected by CVE-2021-1721?
  • Microsoft.NETCore.App (nuget) (versions >= 2.1.0, < 2.1.25)
  • Microsoft.NETCore.App.Host.linux-arm (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-arm64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-musl-arm64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-musl-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.linux-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.osx-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.rhel.6-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-arm (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-arm64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Host.win-x86 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-arm (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-arm64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-musl-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.linux-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.osx-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.rhel.6-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-arm (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-arm64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-x64 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.win-x86 (nuget) (versions >= 3.1.0, < 3.1.12)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-arm (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-arm64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.linux-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.Mono.osx-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-arm (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-arm64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.android-x86 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.browser-wasm (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.ios-arm (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.ios-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.ios-x86 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.linux-musl-arm (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.tvos-arm64 (nuget) (versions >= 5.0.0, < 5.0.3)
  • Microsoft.NETCore.App.Runtime.tvos-x64 (nuget) (versions >= 5.0.0, < 5.0.3)
Is there a fix for CVE-2021-1721?

Yes. CVE-2021-1721 is fixed in 2.1.25, 3.1.12, 5.0.3. Upgrade to this version or later.

Is CVE-2021-1721 exploitable, and should I be worried?

Whether CVE-2021-1721 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo

What actually determines whether CVE-2021-1721 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2021-1721?
  • Upgrade Microsoft.NETCore.App to 2.1.25 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-musl-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-musl-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.linux-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.osx-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.rhel.6-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Host.win-x86 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.osx-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.rhel.6-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x64 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x86 to 3.1.12 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.Mono.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.android-x86 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.browser-wasm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.ios-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.ios-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.ios-x86 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-musl-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.linux-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.osx-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.tvos-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.tvos-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-arm64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x64 to 5.0.3 or later
  • Upgrade Microsoft.NETCore.App.Runtime.win-x86 to 5.0.3 or later

Other vulnerabilities in Microsoft.NETCore.App

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