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Fencer Vulns
medium 6.5

CVE-2026-89044 json

Netty 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

published 2026-09-10 59 d ago modified 2026-09-18 51 d ago also EUVD-2026-75633

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encoding declarations. Attackers can split Transfer-Encoding headers across multiple lines or use values like 'chunked, xchunked' to bypass validation and decode messages as chunked when the final coding is not chunked, enabling request smuggling attacks.

Patch / fix

  • netty netty 4.1.138.Final, 4.2.18.Final
  • netty-tcnative SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.0.84-150200.3.51.1
  • netty SLE Module for Package Hub 15 SP7 4.1.138-150200.4.56.1

suse advisories SUSE-SU-2026:4391-1

  • netty openSUSE Tumbleweed 4.1.138-1.1

opensuse advisories openSUSE-SU-2026:11882-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89044 updated cvss 6.5

netty: Netty: HTTP Request Smuggling via Transfer-Encoding header validation bypass

  • Red Hat AMQ Broker 7 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-transport, +16 more Red Hat AMQ Clients netty-codec, netty-buffer, netty-common, netty-parent, netty-handler, netty-resolver, +9 more Red Hat build of Apache Camel 4 for Quarkus 3 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +9 more Red Hat build of Apache Camel for Spring Boot 4 netty-all, netty-bom, netty-codec, netty-buffer, netty-common, netty-parent, +26 more Red Hat build of Apicurio Registry 3 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +9 more Red Hat build of Debezium 3 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +10 more
    +7 more products
    Red Hat build of Quarkus netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +9 more Red Hat Data Grid 8 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +7 more Red Hat Fuse 7 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +11 more Red Hat JBoss Enterprise Application Platform 7 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +20 more Red Hat JBoss Enterprise Application Platform 8 netty-buffer, netty-codec-http2 Red Hat JBoss Enterprise Application Platform Expansion Pack netty-buffer, netty-codec-http2 Red Hat Single Sign-On 7 netty-codec, netty-buffer, netty-common, netty-handler, netty-resolver, netty-codec-dns, +20 more
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
52 d ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/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

Affected products

  • netty netty

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.