by Kastro CVE-2026-105794
microsoft msquic — MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL
Description · from the CVE record
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.
Affected
ProductAffectedFixed inSource
msquic< 2.4.20–CNA
msquic>= 2.5.0, < 2.5.11–CNA
msquic>= 2.6.0, < 2.6.1–CNA
Scores by source
GitHub_M (CNA)9.1CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial