{"id":"CVE-2026-105794","aliases":["GHSA-w5f4-fx9m-m4q7"],"url":"https://o3.security/vulnerability/CVE-2026-105794","summary":"MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL","details":"MsQuic is a cross-platform C implementation of the IETF QUIC protocol exposed to C, C++, C#, and Rust. Prior to 2.4.20, 2.5.11, and 2.6.1, MsQuic clients using the OpenSSL or QuicTLS TLS backend do not properly verify that a server certificate matches the intended target server hostname. An on-path attacker can therefore present a certificate that does not match the intended target hostname and spoof the server in a man-in-the-middle attack. The Schannel backend is not affected. This issue is fixed in versions 2.4.20, 2.5.11, and 2.6.1.","published":"2026-10-06T14:14:54.483Z","modified":"2026-10-21T09:32:29.024952546Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"NuGet","name":"Microsoft.Native.Quic.MsQuic.OpenSSL","fixedVersion":"2.4.20"},{"ecosystem":"NuGet","name":"Microsoft.Native.Quic.MsQuic.OpenSSL","fixedVersion":"2.5.11"},{"ecosystem":"NuGet","name":"Microsoft.Native.Quic.MsQuic.OpenSSL","fixedVersion":"2.6.1"}],"fix":{"url":"https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412","label":"microsoft/msquic@0591586"},"references":[{"type":"WEB","url":"https://github.com/microsoft/msquic/releases/tag/v2.4.20"},{"type":"WEB","url":"https://github.com/microsoft/msquic/releases/tag/v2.5.11"},{"type":"WEB","url":"https://github.com/microsoft/msquic/releases/tag/v2.6.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105794.json"},{"type":"ADVISORY","url":"https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-105794"},{"type":"FIX","url":"https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412"},{"type":"FIX","url":"https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91"},{"type":"FIX","url":"https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81"},{"type":"FIX","url":"https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83"},{"type":"FIX","url":"https://github.com/microsoft/msquic/pull/6274"},{"type":"FIX","url":"https://github.com/microsoft/msquic/pull/6275"},{"type":"FIX","url":"https://github.com/microsoft/msquic/pull/6276"},{"type":"FIX","url":"https://github.com/microsoft/msquic/pull/6277"},{"type":"PACKAGE","url":"https://github.com/microsoft/msquic"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T09:32:29.024952546Z"}}