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NVD / CVE Program· CNA GitHub_M

CVE-2026-42585: Netty: HTTP Request Smuggling due to malformed Transfer-Encoding

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.26% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: netty netty 4.2.13.Final.

Low priority for now. Upgrade to netty netty 4.2.13.Final or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
May 13, 2026
Updated
Oct 26, 2026
EPSS
0.2% · 18th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.5
CNA · GitHub_M
6.5
1.0 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-42585

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
nettynetty

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • netty nettybefore 4.1.133
  • netty netty4.2.0 and later · before 4.2.13

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • io.netty netty-codec-http

    • >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Finalaffected

  • netty netty

    • >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Finalaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12nettyfrom 0—
Mavenio.netty:netty-codec-httpfrom 4.2.0.Alpha1 · before 4.2.13.Final4.2.13.Final
Mavenio.netty:netty-codec-httpbefore 4.1.133.Final4.1.133.Final
openSUSE:Tumbleweednettybefore 4.1.133-1.14.1.133-1.1
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemisbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-clibefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-commonsbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-core-clientbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-dtobefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-hornetq-protocolbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-hqclient-protocolbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-jdbc-storebefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-jms-clientbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-jms-serverbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-journalbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-rabefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-selectorbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-serverbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-service-extensionsbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-activemq-artemis-toolsbefore 0:2.16.0-22.redhat_00057.1.el7eap0:2.16.0-22.redhat_00057.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-glassfish-jsfbefore 0:2.3.14-11.SP11_redhat_00001.1.el7eap0:2.3.14-11.SP11_redhat_00001.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-ironjacamarbefore 0:1.5.26-2.Final_redhat_00001.1.el7eap0:1.5.26-2.Final_redhat_00001.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-ironjacamar-common-apibefore 0:1.5.26-2.Final_redhat_00001.1.el7eap0:1.5.26-2.Final_redhat_00001.1.el7eap
Red Hat:jboss_enterprise_application_platform_els:7.4::el7eap7-ironjacamar-common-implbefore 0:1.5.26-2.Final_redhat_00001.1.el7eap0:1.5.26-2.Final_redhat_00001.1.el7eap

+96

Same product

netty: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-47691Netty has Insufficient Bailiwick Validation for NS Records
    40Plan
  • CVE-2026-45674Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records
    40Plan
  • CVE-2019-20445HttpObjectDecoder.java in Netty before 4.1.44 allows a Content-Length header to be accompanied by a second Content-Length header, or by a Tr
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-42583May 13, 2026 · Netty: Lz4FrameDecoder resource exhaustion
    30Monitor
  • ← EarlierCVE-2026-42584May 13, 2026 · Netty: HttpClientCodec response desynchronization
    36Monitor
  • Later →CVE-2026-42586May 13, 2026 · Netty: CRLF Injection in Netty Redis Codec Encoder
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
netty netty4.2.13.Final · descriptionVendor (CNA)
Maven:io.netty:netty-codec-http4.1.133.FinalPackage registry (OSV)
Maven:io.netty:netty-codec-http4.2.13.FinalPackage registry (OSV)
opensuse:netty4.1.133-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:eap8-eap-product-conf-parent0:801.7.1-1.GA_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-eap-product-conf-wildfly-ee-feature-pack0:801.7.1-1.GA_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-buffer0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-codec0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-codec-dns0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-codec-http0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-codec-socks0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-common0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-handler0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-handler-proxy0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
red hat:eap8-netty-resolver0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10Package registry (OSV)
suse:netty4.1.133-150200.4.46.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package registry (OSV)
suse:netty-tcnative2.0.77-150200.3.39.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-425810 days apartNetty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization
    39Monitor
  • CVE-2026-425840 days apartNetty: HttpClientCodec response desynchronization
    36Monitor
  • CVE-2026-3387047 days apartNetty: HTTP Request Smuggling via Chunked Extension Quoted-String Parsing
    30Monitor
  • CVE-2026-5990077 days apartNetty codec-http2: Lack of Host Header Deduplication in HTTP/2→HTTP/1.x Translation Leads to Request Routing Bypass
    27Monitor
  • CVE-2026-89044120 days apartNetty 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final HTTP Request Smuggling via Transfer-Encoding
    27Monitor
  • CVE-2026-100659136 days apartNetty 4.2.0 through 4.2.17 HTTP/3 Request Routing Bypass
    27Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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