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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 12
https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4…
security-advisories@github.com
https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f6…
security-advisories@github.com
https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d…
security-advisories@github.com
https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb…
security-advisories@github.com
https://github.com/microsoft/msquic/pull/6274
security-advisories@github.com
https://github.com/microsoft/msquic/pull/6275
security-advisories@github.com
https://github.com/microsoft/msquic/pull/6276
security-advisories@github.com
https://github.com/microsoft/msquic/pull/6277
security-advisories@github.com
https://github.com/microsoft/msquic/releases/tag/v2.4.20
security-advisories@github.com
https://github.com/microsoft/msquic/releases/tag/v2.5.11
security-advisories@github.com
https://github.com/microsoft/msquic/releases/tag/v2.6.1
security-advisories@github.com
https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7
security-advisories@github.com