CVE-2026-89044: netty netty

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

CVSS 6.9 MediumEPSS 0.0028 · 21st percentile

Published by the CVE Program (CNA: VulnCheck) at 10 Sept 2026, 17:39 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
netty	netty https://repo1.maven.org/maven2/io/netty/netty-codec-http/ pkg:maven/io.netty/netty-codec-http	affected 4.1.133.Final to before 4.1.138.Final custom affected 4.2.13.Final to before 4.2.18.Final custom Other versions: unaffected

Identifiers

CVE-2026-89044

CNA

VulnCheck

Weakness (CWE)

CWE-444

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.9	Medium	4.0	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 (VulnCheck)Used for this record
6.5	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0028, the 21st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 10 Sept 2026. New records show when each source confirmed them.

Sources

References from the CNA

github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c vendor-advisory
github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585 patch
github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c patch
github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866 technical-description
github.com/netty/netty/releases/tag/netty-4.1.138.Final release-notes
github.com/netty/netty/releases/tag/netty-4.2.18.Final release-notes
github.com/netty/netty product
www.vulncheck.com/advisories/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 third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.