MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL
Summary
| CVE | CVE-2026-105794 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-06 15:17:16 UTC |
| Updated | 2026-10-06 18:16:47 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 9.1 CRITICAL from [email protected]
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-295 | CWE-295 CWE-295: Improper Certificate Validation
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 9.1 | CRITICAL | 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/E:X/C... |
| 4.0 | CNA | DECLARED | 9.1 | CRITICAL | 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 v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
HighIntegrity
HighAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/microsoft/msquic/releases/tag/v2.5.11 | [email protected] | github.com | |
| github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81 | [email protected] | github.com | |
| github.com/microsoft/msquic/pull/6275 | [email protected] | github.com | |
| github.com/microsoft/msquic/releases/tag/v2.6.1 | [email protected] | github.com | |
| github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412 | [email protected] | github.com | |
| github.com/microsoft/msquic/pull/6276 | [email protected] | github.com | |
| github.com/microsoft/msquic/releases/tag/v2.4.20 | [email protected] | github.com | |
| github.com/microsoft/msquic/pull/6274 | [email protected] | github.com | |
| github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7 | [email protected] | github.com | |
| github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83 | [email protected] | github.com | |
| github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91 | [email protected] | github.com | |
| github.com/microsoft/msquic/pull/6277 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.