CVE-2026-49457

CRITICALPre-NVD 9.19.1
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.1 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: cna:github_m
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 9.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

QUIC has Broken TLS verification

Impact

The QUIC client did not authenticate the server during the TLS 1.3 handshake. The CertificateVerify signature was not checked, the certificate chain was not validated, and the hostname was not compared against the certificate, so verify was effectively a no-op on the client. A man-in-the-middle on the network path could present any certificate and impersonate any server, defeating the confidentiality and integrity of the connection. HTTP/3 uses the same client and was equally affected. Handshakes authenticated by a PSK (session resumption) are not affected, because the peer is authenticated by the PSK binder and no certificate is sent.

Patches

Fixed in 1.4.4. The client now verifies the CertificateVerify signature, validates the certificate chain against the trust store (cacerts option, the operating system store by default), and checks the hostname. Client verify now defaults to on; set verify => false to accept any certificate (for example a self-signed test server).

Workarounds

None before 1.4.4. verify => true had no effect, and inspecting the certificate after connecting does not help because without the signature check the peer is never proven to own the certificate it presents.

Credit

Reported by benmmurphy.

CVSS v3
9.1
EG Score
9.1(low)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

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%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

Published

July 1, 2026

Last Modified

July 1, 2026

Vendor Advisories for CVE-2026-49457(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)
Hex(1)
PackageVulnerable rangeFixed inDependents
quic0.10.0 ... 1.4.3 (25 versions)1.4.4—

Data Freshness Timeline

(refreshed 2× in last 7d / 3× 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. 2026-07-26 13:13 UTCEG score recompute
  2. 2026-07-23 03:18 UTCEG score recompute
  3. 2026-07-01 21:02 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-49457?
CVE-2026-49457 is a critical vulnerability published on July 1, 2026. QUIC has Broken TLS verification Impact The QUIC client did not authenticate the server during the TLS 1.3 handshake. The CertificateVerify signature was not checked, the certificate chain was not validated, and the hostname was not compared against the certificate, so verify was effectively a…
When was CVE-2026-49457 disclosed?
CVE-2026-49457 was first published in the National Vulnerability Database on July 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-49457?
CVE-2026-49457 has a CVSS v4.0 base score of 9.1 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-49457?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49457, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49457

Explore →

Is Your Infrastructure Affected by CVE-2026-49457?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs