CVE-2026-56746CWE-284

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

Medium · published July 21, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
34.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00408 · 34.0th percentile
Weakness
CWE-284 · Improper Access Control
Published
2026-07-21T21:36Z
EPSS history
Timeline
  • 21 JUL 21:36Z
    Netty has a Security Control Bypass via CORS Short-Circuit Failure
    cvelistv5