CVE-2026-56746

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 65% of all CVEs by exploit prediction. 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 — Patch released this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

Netty is a network application framework for development of protocol servers and clients. Versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, are vulnerable to security control bypass during the origin evaluation process. CorsHandler provides a shortCircuit() configuration designed to reject unauthorized cross-origin requests immediately, acting as a security control before requests reach the application. However, due to a logical operator error in the origin evaluation process, this protection can be entirely bypassed. An attacker can bypass the short-circuit mechanism by sending a request with an Origin: null header. This failure forwards unauthorized requests to the backend application, bypassing intended access controls. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
35%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 30, 2026

Advisory Details (3)

Auto-updated Jul 22, 2026
Patch available. Sources: github_release, github.
github Patch Available

Security Control Bypass via CORS Short-Circuit Failure · Advisory · netty/netty · GitHub

https://github.com/netty/netty/security/advisories/GHSA-6cqp-g7gg-8hr5
github_release Patch Available

netty-4.2.16.Final

Patch available: netty/netty netty-4.2.16.Final

https://github.com/netty/netty/releases/tag/netty-4.2.16.Final
github_release Patch Available

netty-4.1.136.Final

Patch available: netty/netty netty-4.1.136.Final

https://github.com/netty/netty/releases/tag/netty-4.1.136.Final

Vendor Advisories for CVE-2026-56746(4)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnetty-codec-http2026-07-30redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
io.netty:netty-codec-http4.0.0.Alpha1 ... 4.1.99.Final (229 versions)4.1.136.Final—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 25× 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. 2026-07-30 16:28 UTCEPSS rescore
  2. 2026-07-30 14:50 UTCEG score recompute
  3. 2026-07-30 14:50 UTCVendor advisory
  4. 2026-07-30 01:41 UTCEG score recompute
  5. 2026-07-30 01:41 UTCVendor advisory
  6. 2026-07-30 01:30 UTCEPSS rescore
  7. 2026-07-30 01:30 UTCEPSS rescore
  8. 2026-07-29 03:35 UTCEG score recompute
  9. 2026-07-28 15:37 UTCEPSS rescore
  10. 2026-07-28 05:41 UTCEG score recompute
  11. 2026-07-27 14:14 UTCEPSS rescore
  12. 2026-07-27 07:46 UTCEG score recompute
  13. 2026-07-26 14:54 UTCEPSS rescore
  14. 2026-07-26 14:54 UTCEPSS rescore
  15. 2026-07-26 09:53 UTCEG score recompute
  16. 2026-07-25 14:18 UTCEPSS rescore
  17. 2026-07-25 14:18 UTCEPSS rescore
  18. 2026-07-24 14:18 UTCEPSS rescore
  19. 2026-07-23 14:18 UTCEPSS rescore
  20. 2026-07-23 03:20 UTCEG score recompute
  21. 2026-07-22 22:42 UTCEG score recompute
  22. 2026-07-22 14:24 UTCEG score recompute
  23. 2026-07-22 14:08 UTCEPSS rescore
  24. 2026-07-21 22:48 UTCEG score recompute
  25. 2026-07-21 22:03 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56746?
CVE-2026-56746 is a medium vulnerability published on July 21, 2026. Netty is a network application framework for development of protocol servers and clients. Versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, are vulnerable to security control bypass during the origin evaluation process. CorsHandler provides a shortCircuit()…
When was CVE-2026-56746 disclosed?
CVE-2026-56746 was first published in the National Vulnerability Database on July 21, 2026, with the most recent update on July 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56746 actively exploited?
CVE-2026-56746 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 64.5% of all scored CVEs.
What is the CVSS score of CVE-2026-56746?
CVE-2026-56746 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-56746?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56746, 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-2026-56746

Explore →

Is Your Infrastructure Affected by CVE-2026-56746?

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

Start Free Scan →Browse All CVEs