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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-56746
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-21 22:17:14 UTC
Updated2026-07-22 20:35:40 UTC
DescriptionNetty 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

EPSS: 0.004780000 probability, percentile 0.384360000 (date 2026-07-22)

Problem Types: CWE-284 | CWE-284 CWE-284: Improper Access Control

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Netty Netty affected >= 4.2.0.Final, < 4.2.16.Final Not specified
CNA Netty Netty affected >= 4.1.0.Final, < 4.1.136.Final Not specified

References

ReferenceSourceLinkTags
github.com/netty/netty/releases/tag/netty-4.1.136.Final [email protected] github.com
github.com/netty/netty/releases/tag/netty-4.2.16.Final [email protected] github.com
github.com/netty/netty/security/advisories/GHSA-6cqp-g7gg-8hr5 [email protected] github.com
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