Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / maven/io.netty/netty-codec-http/CVE-2026-56746
Advisory ID gitlab/maven/io.netty/netty-codec-http/CVE-2026-56746
Aliases CVE-2026-56746
GHSA-6cqp-g7gg-8hr5
Summary Netty: Security Control Bypass via CORS Short-Circuit Failure Netty's 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.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (3)
CWE-284 Improper Access Control
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-codec-http/CVE-2026-56746.yml
Reference id Reference type URL
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final
https://github.com/netty/netty/security/advisories/GHSA-6cqp-g7gg-8hr5
https://nvd.nist.gov/vuln/detail/CVE-2026-56746
GHSA-6cqp-g7gg-8hr5 https://github.com/advisories/GHSA-6cqp-g7gg-8hr5
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-codec-http/CVE-2026-56746.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-07-22T13:39:33Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/56xxx/CVE-2026-56746.json

Source Advisory: vulnrichment/CVE-2026-56746

View SSVC decision tree 
[{'Exploitation': 'none'},
 {'Automatable': 'no'},
 {'Technical Impact': 'partial'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]