GHSA-w5f4-fx9m-m4q7

Suggest an improvement
Source
https://github.com/advisories/GHSA-w5f4-fx9m-m4q7
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-w5f4-fx9m-m4q7/GHSA-w5f4-fx9m-m4q7.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-w5f4-fx9m-m4q7
Aliases
Published
2026-10-06T15:33:08Z
Modified
2026-10-06T15:46:49Z
Severity
  • 9.1 (Critical) CVSS_V4 - 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 CVSS Calculator
Summary
MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL
Details

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.

Database specific 
{
    "cwe_ids": [
        "CWE-295"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-06T15:33:08Z",
    "nvd_published_at": "2026-10-06T15:17:16Z",
    "severity": "CRITICAL"
}
References

Affected packages

NuGet
Microsoft.Native.Quic.MsQuic.OpenSSL

Package

Name
Microsoft.Native.Quic.MsQuic.OpenSSL
View open source insights on deps.dev
Purl
pkg:nuget/Microsoft.Native.Quic.MsQuic.OpenSSL

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.4.20

Affected versions

1.*
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"
Microsoft.Native.Quic.MsQuic.OpenSSL

Package

Name
Microsoft.Native.Quic.MsQuic.OpenSSL
View open source insights on deps.dev
Purl
pkg:nuget/Microsoft.Native.Quic.MsQuic.OpenSSL

Affected ranges

Type
ECOSYSTEM
Events
Introduced
2.5.0
Fixed
2.5.11

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"
Microsoft.Native.Quic.MsQuic.OpenSSL

Package

Name
Microsoft.Native.Quic.MsQuic.OpenSSL
View open source insights on deps.dev
Purl
pkg:nuget/Microsoft.Native.Quic.MsQuic.OpenSSL

Affected ranges

Type
ECOSYSTEM
Events
Introduced
2.6.0
Fixed
2.6.1

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"