{"id":"CVE-2021-1721","aliases":["BIT-dotnet-2021-1721","BIT-dotnet-sdk-2021-1721","GHSA-3gp9-h8hw-pxpw"],"url":"https://o3.security/vulnerability/CVE-2021-1721","summary":"Denial of service in .NET core","details":".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.","published":"2021-02-25T23:15:13.210Z","modified":"2026-09-22T03:45:17.675257742Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"NuGet","name":"Microsoft.NETCore.App","fixedVersion":"2.1.25"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.linux-arm","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.linux-arm64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.linux-musl-arm64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.linux-musl-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.linux-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.osx-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.rhel.6-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.win-arm","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.win-arm64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.win-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Host.win-x86","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-arm","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-arm64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-musl-arm64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-musl-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.osx-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.rhel.6-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-arm","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-arm64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-x64","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-x86","fixedVersion":"3.1.12"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.linux-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.LLVM.AOT.osx-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.LLVM.linux-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.LLVM.osx-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.linux-arm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.linux-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.linux-musl-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.linux-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.Mono.osx-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.android-arm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.android-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.android-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.android-x86","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.browser-wasm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.ios-arm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.ios-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.ios-x86","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-arm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-musl-arm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-musl-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-musl-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.linux-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.osx-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.tvos-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.tvos-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-arm","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-arm64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-x64","fixedVersion":"5.0.3"},{"ecosystem":"NuGet","name":"Microsoft.NETCore.App.Runtime.win-x86","fixedVersion":"5.0.3"}],"fix":null,"references":[{"type":"FIX","url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1721"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-1721"},{"type":"WEB","url":"https://github.com/dotnet/announcements/issues/175"},{"type":"WEB","url":"https://github.com/dotnet/runtime/issues/48067"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-22T03:45:17.675257742Z"}}