CVE-2026-42584
What it is
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
At a glance
- Exploitability
- Can be exploited over the network without logging in. Limited direct impact.
- Exploit odds
- 0.8% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.8% in the next 30 days (EPSS).
- Severity: 7.3 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.8% · EPSS, next 30 days
- Weakness
- CWE-444
- Record status
- Modified
Affected
- Netty < 4.1.133
- Netty < 4.2.13
Attack profile CVSS 3.1 · 7.3
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-42584.md and follow it. Check whether this project is affected by CVE-2026-42584. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3
- https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3
References
- https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3
- https://access.redhat.com/errata/RHSA-2026:23808
- https://access.redhat.com/errata/RHSA-2026:24502
- https://access.redhat.com/errata/RHSA-2026:25123
- https://access.redhat.com/errata/RHSA-2026:28010
- https://access.redhat.com/errata/RHSA-2026:36820
- https://access.redhat.com/errata/RHSA-2026:37390
- https://access.redhat.com/errata/RHSA-2026:42644
- https://access.redhat.com/errata/RHSA-2026:49700
- https://access.redhat.com/errata/RHSA-2026:49701
- https://access.redhat.com/errata/RHSA-2026:53644
- https://access.redhat.com/errata/RHSA-2026:53645
- https://access.redhat.com/errata/RHSA-2026:53646
- https://access.redhat.com/errata/RHSA-2026:54435
- https://access.redhat.com/errata/RHSA-2026:65126
- https://access.redhat.com/errata/RHSA-2026:66488
- https://access.redhat.com/errata/RHSA-2026:66545
- https://access.redhat.com/security/cve/CVE-2026-42584
- https://bugzilla.redhat.com/show_bug.cgi?id=2477224
- https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42584.json