← Vulnerability feed

Vulnerability record · CVE-2026-56816 · published 21 July 2026

CVE-2026-56816: Netty uncontrolled resource consumption vulnerability

Netty · Netty

Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's `Http3FrameCodec` buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; `decodeFrame` trusts `payLoadLength`, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.

7.5 CVSS 3.1 High EPSS 0.64% · top 51.2% CWE-400 · Uncontrolled resource consumption
7.5CVSS 3.1 base score
0.64%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
7 Aug 2026Last modified by NVD

Description

Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's `Http3FrameCodec` buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; `decodeFrame` trusts `payLoadLength`, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b Patch
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final Release Notes
https://github.com/netty/netty/security/advisories/GHSA-hpcc-26xq-25fv ExploitVendor Advisory

Track CVE-2026-56816 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2023-44487HTTP/2 Rapid Reset stream cancellation denial of serviceThe HTTP/2 protocol permits a client to cancel many streams quickly, and the server's handling of those resets consumes disproportionate resources. T…KEVEPSS 100%analysed10.0CVE-2026-47691Netty insufficient verification of data authenticity vulnerabilityNetty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's `…EPSS 0.36%10.0CVE-2026-45674Netty insufficient verification of data authenticity vulnerabilityNetty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's D…EPSS 0.36%9.8CVE-2026-42581Netty http request smuggling vulnerabilityNetty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpObjectDecoder strips a conflicting…EPSS 0.68%9.1CVE-2026-75595Netty vulnerabilityNetty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHand…EPSS 0.46%9.1CVE-2026-56820Netty improper certificate validation vulnerabilityNetty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and prior to 4…EPSS 0.31%9.1CVE-2026-42584Netty http request smuggling vulnerabilityNetty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound res…EPSS 0.72%9.1CVE-2026-42579Netty improper input validation vulnerabilityNetty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC…EPSS 0.85%

Source: NIST National Vulnerability Database (record CVE-2026-56816), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.