MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL

{
  "id": "16578d8495ed1f8bc8ea9f28b196dacb44056cf167321a992366bbcab4d4a328",
  "url": "https://osv.dev/vulnerability/GHSA-w5f4-fx9m-m4q7",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL",
    "summary": "# Summary Improper TLS hostname verification allows a man-in-the-middle (MITM) attack on MsQuic. # Details Only MsQuic with the OpenSSL and QuicTLS TLS backends is affected (the Schannel backend is not affected). ## Patches 2.6.1, 2.5.11, and 2.4.20 # Impact An on-path attacker could spoof a server identity by using a certificate that doesn't match the intended target server hostname.",
    "evidence": "osv:GHSA-w5f4-fx9m-m4q7",
    "products": [
      {
        "name": {
          "value": "Microsoft.Native.Quic.MsQuic.OpenSSL",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.4.20",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "1.8.0",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "Microsoft.Native.Quic.MsQuic.OpenSSL",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.5.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Microsoft.Native.Quic.MsQuic.OpenSSL",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.6.1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "GHSA-w5f4-fx9m-m4q7",
      "aliases": [
        "CVE-2026-105794",
        "GHSA-w5f4-fx9m-m4q7"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.4.20"
                }
              ]
            }
          ],
          "package": {
            "name": "Microsoft.Native.Quic.MsQuic.OpenSSL",
            "purl": "pkg:nuget/Microsoft.Native.Quic.MsQuic.OpenSSL",
            "ecosystem": "NuGet"
          },
          "versions": [
            "1.8.0"
          ],
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-w5f4-fx9m-m4q7/GHSA-w5f4-fx9m-m4q7.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.5.0"
                },
                {
                  "fixed": "2.5.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Microsoft.Native.Quic.MsQuic.OpenSSL",
            "purl": "pkg:nuget/Microsoft.Native.Quic.MsQuic.OpenSSL",
            "ecosystem": "NuGet"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-w5f4-fx9m-m4q7/GHSA-w5f4-fx9m-m4q7.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.0"
                },
                {
                  "fixed": "2.6.1"
                }
              ]
            }
          ],
          "package": {
            "name": "Microsoft.Native.Quic.MsQuic.OpenSSL",
            "purl": "pkg:nuget/Microsoft.Native.Quic.MsQuic.OpenSSL",
            "ecosystem": "NuGet"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-w5f4-fx9m-m4q7/GHSA-w5f4-fx9m-m4q7.json"
          }
        }
      ],
      "modified": "2026-10-06T15:46:49.195357428Z",
      "provider": "osv",
      "references": [
        "https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-105794",
        "https://github.com/microsoft/msquic/pull/6274",
        "https://github.com/microsoft/msquic/pull/6275",
        "https://github.com/microsoft/msquic/pull/6276",
        "https://github.com/microsoft/msquic/pull/6277",
        "https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412",
        "https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91",
        "https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81",
        "https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83",
        "https://github.com/microsoft/msquic",
        "https://github.com/microsoft/msquic/releases/tag/v2.4.20",
        "https://github.com/microsoft/msquic/releases/tag/v2.5.11",
        "https://github.com/microsoft/msquic/releases/tag/v2.6.1"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-295"
        ],
        "severity": "CRITICAL",
        "github_reviewed": true,
        "nvd_published_at": "2026-10-06T15:17:16Z",
        "github_reviewed_at": "2026-10-06T15:33:08Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-105794",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 89265,
  "published_at": "2026-10-06T15:33:08+00:00"
}