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.
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Affected Vendors & Products
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History
Fri, 09 Oct 2026 09:15:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Microsoft
Microsoft msquic |
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| Vendors & Products |
Microsoft
Microsoft msquic |
Tue, 06 Oct 2026 14:30:00 +0000
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| 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. | |
| Title | MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL | |
| Weaknesses | CWE-295 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-10-06T14:14:54.483Z
Updated: 2026-10-06T17:40:05.706Z
Reserved: 2026-10-05T20:37:19.364Z
Link: CVE-2026-105794
No data.
Status : Awaiting Analysis
Published: 2026-10-06T15:17:16.260
Modified: 2026-10-06T18:16:47.073
Link: CVE-2026-105794
No data.