CVE-2026-105794
MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-295 |
| Vendor | microsoft |
| Product | msquic |
| Ecosystems | |
| Industries | TechnologyEnterprise |
| Published | Oct 6, 2026 |
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Affected Versions
microsoft / msquic
< 2.4.20 >= 2.5.0, < 2.5.11 >= 2.6.0, < 2.6.1
References
github.com: https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7 github.com: https://github.com/microsoft/msquic/pull/6274 github.com: https://github.com/microsoft/msquic/pull/6275 github.com: https://github.com/microsoft/msquic/pull/6276 github.com: https://github.com/microsoft/msquic/pull/6277 github.com: https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412 github.com: https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91 github.com: https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81 github.com: https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83 github.com: https://github.com/microsoft/msquic/releases/tag/v2.4.20 github.com: https://github.com/microsoft/msquic/releases/tag/v2.5.11 github.com: https://github.com/microsoft/msquic/releases/tag/v2.6.1