7.5

CVE-2026-56816: netty Uncontrolled Resource Consumption

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-56816DEBIAN-CVE-2026-56816CGA-26qj-rj3h-464j
Published 21-07-2026Last modified 22-07-2026
Open JSON

Vulnerability summary

CVE-2026-56816 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in netty. EPSS estimates a 0.64% chance of exploitation in the next 30 days, higher than 49.9% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
40/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.64%
0%100%
Low · +0.12 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-GJJW-MQ4V-PH4F

Timeline

  1. 21-07-2026
    PublishedVulnerability first disclosed.
  2. 22-07-2026
    Last modifiedVulnerability information updated.

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 metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.64%

Chance of exploitation in the next 30 days

Percentile

50%

Versus all other CVEs

30-day change

+0.12 pp

From 0.52% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.64%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • githubUnverified

    Netty

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Chainguard35 products
  • apache-hop< 2.18.1-r11
  • apache-hop-fips< 2.18.1-r6
  • camunda-8.9< 8.9.13-r2
  • camunda-zeebe-8.9< 8.9.13-r1
  • celeborn-0.7< 0.7.0-r10
Wolfi20 products
  • kafka_exporter-strimzi-compat< 1.2.0-r4 | < 1.2.0-r5
  • kafka-strimzi-compat< 1.2.0-r5
  • opensearch-3< 3.7.0-r5
  • opensearch-3-discovery-ec2< 3.8.0-r3
  • opensearch-3-iamguarded-compat< 3.8.0-r3
Debian1 product
  • nettyAll versions (No fix recorded)
Io.netty1 product
  • netty-codec-http3< 4.2.16.Final
Netty1 product
  • netty< 4.2.16.Final | ≥ 4.2.2, < 4.2.16
Ubuntu1 product
  • nettyAll versions (No fix recorded)

6 vendors · 59 products

References

9 links