CVE-2026-105794 MsQuic - Man-in-the-Middle

MsQuic < 2.4.20, < 2.5.11, and < 2.6.1 contain a man-in-the-middle vulnerability caused by improper server certificate hostname verification in OpenSSL and QuicTLS backends, letting on-path attackers spoof servers, exploit requires network position.

CVSS base score 9.1 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
1.00% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Man-in-the-Middle
Impact
Man In The Middle, Information Disclosure, Data Tampering
CVSS 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
Published
6 October 2026
Updated
15 October 2026
Weakness
CWE-295

Vendor fix

Update to versions 2.4.20, 2.5.11, or 2.6.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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