Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | >= 4.1.0, < 4.1.136 |
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/releases/tag/netty-4.1.136.FinalRelease Notes
- https://github.com/netty/netty/releases/tag/netty-4.2.16.FinalRelease Notes
- https://github.com/netty/netty/security/advisories/GHSA-6cqp-g7gg-8hr5Vendor Advisory
FAQ
What is CVE-2026-56746?
CVE-2026-56746 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 co...
How severe is CVE-2026-56746?
CVE-2026-56746 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-56746?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.