CVE-2026-105794: critical vulnerability in microsoft msquic
MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL
Published
28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.1epss 1.0%
exploitation probability
1.0%top 38% of all CVEs
observed exploitation
nono source reports it
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.
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 products
microsoft · msquicReferences
https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83https://github.com/microsoft/msquic/pull/6274https://github.com/microsoft/msquic/pull/6275https://github.com/microsoft/msquic/pull/6276https://github.com/microsoft/msquic/pull/6277https://github.com/microsoft/msquic/releases/tag/v2.4.20https://github.com/microsoft/msquic/releases/tag/v2.5.11https://github.com/microsoft/msquic/releases/tag/v2.6.1https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7