CVE-2026-105794

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.0% (61st percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
41
EG Risk 41/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation1% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
1.0%
EPSS %ILE
61st
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 6, 2026

Last Modified

October 6, 2026

Advisory Details (10)

Auto-updated Oct 6, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

v2.4.20

Patch available: microsoft/msquic v2.4.20

https://github.com/microsoft/msquic/releases/tag/v2.4.20
github_commit Patch Available

commit a01333cf7c26 (microsoft/msquic)

Patch available: microsoft/msquic v2.6.1 (contains commit a01333cf7c26)

https://github.com/microsoft/msquic/commit/a01333cf7c2659cce0ff03ef3f21e1ff15bb5b83
github_commit Patch Available

commit 90fd45498bf9 (microsoft/msquic)

Patch available: microsoft/msquic v2.4.20 (contains commit 90fd45498bf9)

https://github.com/microsoft/msquic/commit/90fd45498bf9b506b8556fb407088688474d6c81
github_commit

commit 508e811370df (microsoft/msquic)

Fix landed in microsoft/msquic commit 508e811370df — awaiting tagged release

https://github.com/microsoft/msquic/commit/508e811370df93e2ad848f5c78347d4fe4f65a91
github_commit Patch Available

commit 0591586443cc (microsoft/msquic)

Patch available: microsoft/msquic v2.5.11 (contains commit 0591586443cc)

https://github.com/microsoft/msquic/commit/0591586443cc73a2d2cfb679527d91a144b4a412
github_pr Patch Available

[CP] Fix hostname validation with OpenSSL/QuicTLS (#6274)

Patch available: microsoft/msquic v2.4.20 (PR #6277 merged 2026-08-28)

https://github.com/microsoft/msquic/pull/6277
github_pr Patch Available

[CP] Fix hostname validation with OpenSSL/QuicTLS (#6274)

Patch available: microsoft/msquic v2.5.11 (PR #6276 merged 2026-08-28)

https://github.com/microsoft/msquic/pull/6276
github_pr Patch Available

[CP] Fix hostname validation with OpenSSL/QuicTLS (#6274)

Patch available: microsoft/msquic v2.6.1 (PR #6275 merged 2026-08-28)

https://github.com/microsoft/msquic/pull/6275
github_pr

Fix hostname validation with OpenSSL/QuicTLS

Fix merged in microsoft/msquic PR #6274 on 2026-08-28 — awaiting tagged release

https://github.com/microsoft/msquic/pull/6274
githubMentions a patch (unverified)

Improper Certificate Validation in Microsoft.Native.Quic.MsQuic.OpenSSL · Advisory · microsoft/msquic · GitHub

https://github.com/microsoft/msquic/security/advisories/GHSA-w5f4-fx9m-m4q7

Vendor Advisories for CVE-2026-105794(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
NuGet(1)
PackageVulnerable rangeFix by version rangeDependents
Microsoft.Native.Quic.MsQuic.OpenSSL1.8.0
  • every version up to 2.4.20: fixed in 2.4.20
  • 2.5.0 up to 2.5.11: fixed in 2.5.11
  • 2.6.0 up to 2.6.1: fixed in 2.6.1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 11× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-09 20:51 UTCEG score recompute
  2. 2026-10-09 20:06 UTCEPSS rescore
  3. 2026-10-08 20:04 UTCEG score recompute
  4. 2026-10-08 17:11 UTCEPSS rescore
  5. 2026-10-08 03:32 UTCEG score recompute
  6. 2026-10-07 23:47 UTCEPSS rescore
  7. 2026-10-06 18:32 UTCEG score recompute
  8. 2026-10-06 17:47 UTCEG score recompute
  9. 2026-10-06 15:27 UTCEG score recompute
  10. 2026-10-06 14:30 UTCEG score recompute
  11. 2026-10-06 14:29 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-105794?
CVE-2026-105794 is a critical vulnerability published on October 6, 2026. 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…
When was CVE-2026-105794 disclosed?
CVE-2026-105794 was first published on October 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-105794 actively exploited?
CVE-2026-105794 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (61st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-105794?
CVE-2026-105794 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-105794?
A fix for CVE-2026-105794 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-105794 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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