CVE-2026-56746

Netty has a Security Control Bypass via CORS Short-Circuit Failure

Published Jul 21, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-6cqp-g7gg-8hr5 Netty: Security Control Bypass via CORS Short-Circuit Failure
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Netty
Netty netty
Vendors & Products Netty
Netty netty
Type Values Removed Values Added
Description 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.
Title Netty has a Security Control Bypass via CORS Short-Circuit Failure
Weaknesses CWE-284
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 22, 2026, 1:39 PM
Reserved
Jun 22, 2026, 7:17 PM
Status
Analyzed
Published
Jul 21, 2026, 10:17 PM
Modified
Jul 30, 2026, 2:47 PM
Severity
Important
Public date
Jul 21, 2026, 9:36 PM