{"id":"CVE-2023-38171","aliases":["BIT-dotnet-2023-38171","BIT-dotnet-sdk-2023-38171","GHSA-xh5m-8qqp-c5x7"],"url":"https://o3.security/vulnerability/CVE-2023-38171","summary":"Remote Denial of Service Vulnerability in Microsoft.Native.Quic.MsQuic.Schannel","details":"### Impact\nThe MsQuic server application or process will crash, resulting in a denial of service.\n\n### Patches\nThe following patch was made:\n\n- Don't Allow Version Negotiation Packets for Server Connections - https://github.com/microsoft/msquic/commit/3226cff07d22662f16fc98d605656860e64cd343\n\n### Workarounds\nBeyond upgrading to the patched versions, there is no other workaround. You must upgrade or disable MsQuic functionality.\n","published":"2023-10-10T18:15:18.087Z","modified":"2026-10-24T10:30:52.492853590Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.69706,"percentile":0.99334,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"NuGet","name":"Microsoft.Native.Quic.MsQuic.Schannel","fixedVersion":"2.2.3"},{"ecosystem":"NuGet","name":"Microsoft.Native.Quic.MsQuic.OpenSSL","fixedVersion":"2.2.3"}],"fix":{"url":"https://github.com/microsoft/msquic/commit/3226cff07d22662f16fc98d605656860e64cd343","label":"microsoft/msquic@3226cff"},"references":[{"type":"FIX","url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-38171"},{"type":"WEB","url":"https://github.com/microsoft/msquic/security/advisories/GHSA-xh5m-8qqp-c5x7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-38171"},{"type":"WEB","url":"https://github.com/microsoft/msquic/commit/3226cff07d22662f16fc98d605656860e64cd343"},{"type":"PACKAGE","url":"https://github.com/microsoft/msquic"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-24T10:30:52.492853590Z"}}