EUVD-2026-93422Published

MsQuic: Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

CVE-2026-105794

No KEV entry is attached to this observation; this is not evidence that exploitation is absent.

FIRST EPSS: 1.00 % · percentile 63.12 % · scored 10 Nov 2026.

Observed 10 Nov 2026 20:24:10 UTC · Complete immutable risk JSON

cve-program · CVE-2026-105794

Published

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.

Source published: 6 Oct 2026 14:14:54 UTC
Source modified: 6 Oct 2026 17:40:05 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 9.1 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

euvd · EUVD-2026-93422

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Oct 6, 2026, 2:14:54 PM

dateUpdated: Oct 6, 2026, 5:40:05 PM

Source published: Oct 6, 2026, 2:14:54 PM (timezone not stated)
Source modified: Oct 6, 2026, 5:40:05 PM (timezone not stated)
Observed here: 11 Nov 2026 05:31:11 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 9.1 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

nvd · CVE-2026-105794

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Awaiting Analysis

Weakness classifications: CWE-295

Original publisher date fields

published: 2026-10-06T15:17:16.260

lastModified: 2026-10-06T18:16:47.073

Source published: 6 Oct 2026 15:17:16 UTC
Source modified: 6 Oct 2026 18:16:47 UTC
Observed here: 25 Oct 2026 04:17:29 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 9.1 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/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

osv · GHSA-w5f4-fx9m-m4q7

Published

# Summary Improper TLS hostname verification allows a man-in-the-middle (MITM) attack on MsQuic. # Details Only MsQuic with the OpenSSL and QuicTLS TLS backends is affected (the Schannel backend is not affected). ## Patches 2.6.1, 2.5.11, and 2.4.20 # Impact An on-path attacker could spoof a server identity by using a certificate that doesn't match the intended target server hostname.

Source published: 6 Oct 2026 15:33:08 UTC
Source modified: 6 Oct 2026 15:46:49 UTC
Observed here: 23 Oct 2026 16:01:25 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · 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

Publisher rating · CRITICAL