Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Netty's netty-codec-http package, versions 4.2.0.Final before 4.2.16.Final and versions before 4.1.136.Final, has a flaw in its CORS handler where the shortCircuit() setting can be bypassed. An attacker who can send HTTP requests can send an Origin: null header to get unauthorized cross-origin requests forwarded to the backend application, bypassing access controls. Upgrade to 4.2.16.Final or 4.1.136.Final.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 6.5 | Medium | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0041, the 35th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:16 UTC First seen by agentprime
- 31 Oct 2026, 14:16 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-6cqp-g7gg-8hr5
- OSV: GHSA-6cqp-g7gg-8hr5
- github.com/netty/netty/security/advisories/GHSA-6cqp-g7gg-8hr5
- nvd.nist.gov/vuln/detail/CVE-2026-56746
- github.com/netty/netty
- github.com/netty/netty/releases/tag/netty-4.1.136.Final
- github.com/netty/netty/releases/tag/netty-4.2.16.Final