CVE-2026-105794
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering.
- Exploit odds
- 1.0% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 1.0% in the next 30 days (EPSS).
- Severity: 9.1 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 1.0% · EPSS, next 30 days
- Weakness
- CWE-295 · Improper certificate validation
- Record status
- Awaiting Analysis
Attack profile CVSS 4.0 · 9.1
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Raw vector
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-105794.md and follow it. Check whether this project is affected by CVE-2026-105794. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412
- https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91
- https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81
- https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83
- https://github.com/microsoft/msquic/pull/6274
- https://github.com/microsoft/msquic/pull/6275
- https://github.com/microsoft/msquic/pull/6276
- https://github.com/microsoft/msquic/pull/6277
- https://github.com/microsoft/msquic/releases/tag/v2.4.20
- https://github.com/microsoft/msquic/releases/tag/v2.5.11
References
- https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412
- https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91
- https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81
- https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83
- https://github.com/microsoft/msquic/pull/6274
- https://github.com/microsoft/msquic/pull/6275
- https://github.com/microsoft/msquic/pull/6276
- https://github.com/microsoft/msquic/pull/6277
- https://github.com/microsoft/msquic/releases/tag/v2.4.20
- https://github.com/microsoft/msquic/releases/tag/v2.5.11
- https://github.com/microsoft/msquic/releases/tag/v2.6.1
- https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7