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No exploitation reportedFix available

CVE-2026-56745

No exploitation reported by the sources we read.

  • Published2026-07-21
  • Fixed in4.2.16 · 4.1.136
  • WeaknessCWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Timeline

dates in UTC
  1. 2026-07-2122:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-04 03:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-56745?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-56745?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Netty
BranchAffectedFixed in
4.2≥ 4.2.0, < 4.2.164.2.16
4.1≥ 4.1.0, < 4.1.1364.1.136
netty-codec-http
BranchAffectedFixed in
4.2≥ 4.2.0.Final, < 4.2.16.Final4.2.16.Final
4.1≥ 4.1.0.Final, < 4.1.136.Final4.1.136.Final

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • akhqWolfiall versions · fixed in 0.27.1-r12
  • akhqChainguardall versions · fixed in 0.27.1-r12
  • apache-activemq-artemisWolfiall versions · fixed in 2.55.0-r1
  • apache-activemq-artemisMinimOSall versions · fixed in 2.56.0-r0
  • apache-activemq-artemisCleanStartall versions · fixed in 2.56.0-r1
  • apache-activemq-artemisChainguardall versions · fixed in 2.55.0-r1
  • apache-druidMinimOSall versions · fixed in 38.0.0-r0and 1 other package
  • apache-hiveCleanStartall versions · fixed in 3.1.3-r3

185 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-56745 Red Hat Product Security492 products fixed · 32 known affected

    netty: io.netty/netty-codec-http: Netty: Denial of Service via memory exhaustion in SPDY-to-HTTP codec

    openshift-serverless-1/kn-ekb-dispatcher-rhel9 as a component of OpenShift Serverless · openshift-serverless-1/kn-ekb-receiver-rhel9 as a component of OpenShift Serverless · openshift-serverless-1/kn-eventing-integrations-aws-ddb-streams-source-rhel9 as a component of OpenShift Serverless · +29 more

  • RHSA-2026:90321 Red Hat Product Security8 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.31.0 Release.

  • RHSA-2026:84734 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: RHOAI 3.4.5 - Red Hat OpenShift AI

  • RHSA-2026:76637 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Apicurio Registry (container images) release and security update [ 3.3.3 GA ]

  • RHSA-2026:70277 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.8 security update

  • RHSA-2026:70230 Red Hat Product Security147 products fixed

    Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.8 security update

16 more advisories

Full record on NVD

Fix

  1. Update Netty to 4.2.16 · 4.1.136
  2. Vendor fix Red Hat Product Security RHSA-2026:90321 · 8 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2026:84734 · 4 productsFor Red Hat OpenShift AI 3.4.5 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
  4. Vendor fix Red Hat Product Security RHSA-2026:76637 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  5. Vendor fix Red Hat Product Security RHSA-2026:70277 · 2 productsBefore applying the update, make sure all previously released errata relevant to your system have been applied. Also, back up your existing installation, including all applications, configuration files, databases and database settings. For details on how to apply this update, refer to: https://acce…
  6. Vendor fix Red Hat Product Security RHSA-2026:69296 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  7. Vendor fix Red Hat Product Security RHSA-2026:68333 · 6 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionnone2026-07-22
  • OpenCVESSVC decisionnone—
  • CNACVSS 4.08.7known since 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-400known since 2026-10-23
  • FIRST EPSSEPSS score0.6 %2026-11-03
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2026-07-22

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-07-21
Last Modified
2026-07-30
NVD status
Analyzed
GitHub Advisory
GHSA-jppx-w49h-x2qq

Frequently asked questions

What is CVE-2026-56745?

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Is CVE-2026-56745 actively exploited?

Active exploitation of CVE-2026-56745 has not been confirmed. Its EPSS score was 0.6% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-56745?

CVE-2026-56745 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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