`CVE-2026-89044`

6.9 Medium No exploit published

Published 5 days ago. NVD backfills CPE data for days or weeks after publication, and OSV and the exploit indexes lag too. Scope and status here may change.

Description

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.

CWE-444

Exploitation Status

No public exploit

Nothing published shows this CVE being exploited, which is not the same as ruling it out.

CVSS E:U

CISA KEV not listed
CISA Vulnrichment no assessment published
Indexed PoC none indexed
EPSS 0.25% chance in 30 days

Waratek Defense Posture

No exploit published

In RASP's scope with an upstream fix path, but nobody has published a working exploit. That is a statement about what has been published, not a finding that the defect is unreachable or unimportant.

Protection none
Action unverified patch rule
Review automated upstream-data
Record active

Decided by below-action-threshold : Medium or Low severity, no KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory

Finding This CVE is MEDIUM severity, is not listed in CISA KEV, has no public exploit or PoC in any indexed source, carries no CISA Vulnrichment finding of a demonstrated exploit, and is not part of an Oracle Critical Patch Update. None of the signals that would put it in front of an engineer is present, and the volume of CVEs below that bar is too great to take one at a time, so no rule is written for it. This is a decision about what we act on, not a finding that the CVE is harmless — a patch may well be derivable, and a low-severity defect can still be one link in a longer chain.

Candidate fix https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c : a commit: the change itself

Decided by	`below-action-threshold` : Medium or Low severity, no KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory
Finding	This CVE is MEDIUM severity, is not listed in CISA KEV, has no public exploit or PoC in any indexed source, carries no CISA Vulnrichment finding of a demonstrated exploit, and is not part of an Oracle Critical Patch Update. None of the signals that would put it in front of an engineer is present, and the volume of CVEs below that bar is too great to take one at a time, so no rule is written for it. This is a decision about what we act on, not a finding that the CVE is harmless — a patch may well be derivable, and a low-severity defect can still be one link in a longer chain.
Candidate fix	https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c : a commit: the change itself

CVSS

6.9 MEDIUM v4.0

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/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

2 metrics

VRT selects the newest version's highest entry and publishes it as cvssScore, newest rather than largest because scores are not comparable across versions, and highest rather than first because the first entry is frequently a CNA placeholder scoring 0.0 over NVD's own analysis.

Version Score Band Vector Assigner Type

CVSS 4.0 6.9 MEDIUM 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 disclosure@vulncheck.com Secondary published

CVSS 3.1 6.5 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N disclosure@vulncheck.com Primary

Version	Score	Band	Vector	Assigner	Type
CVSS 4.0	6.9	MEDIUM	`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`	disclosure@vulncheck.com	Secondary	published
CVSS 3.1	6.5	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`	disclosure@vulncheck.com	Primary

References

URL	Tags
https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c	commit
https://github.com/netty/netty
https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866
https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585
https://github.com/netty/netty/releases/tag/netty-4.1.138.Final
https://github.com/netty/netty/releases/tag/netty-4.2.18.Final
https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c
https://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

URL

Timeline

Published 2026-09-10 Last modified 2026-09-10

Published	2026-09-10	By the CVE Program.
NVD record modified	2026-09-10	NVD's own last-modified date for this record.

Published

2026-09-10

By the CVE Program.

NVD record modified

2026-09-10

NVD's own last-modified date for this record.

Pipeline policy audit (16 of 21 rules evaluated)

16 of 21 rules ran. The rest were never reached, because an earlier stage settled the CVE, a distinct claim from a rule that ran and found nothing.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? first match wins

1 rejected no-match CVE Program withdrawal of this identifier

scope: Is the vulnerability ARMR's to address? first match wins

2 armr-patch-file no-match An ARMR patch file on disk for this CVE

3 armr-secure-rule-file no-match An ARMR security-rule template on disk for this CVE

4 manual-classification no-match A researcher's recorded decision for this specific CVE

5 manual classification no-match Manual classification of this CVE in the legacy dataset

6 non-java-upstream no-match A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component no-match The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the native WebLogic proxy plug-in. Oracle gives these no CPE of their own and names them only in the description.

8 osv-maven no-match An OSV.dev record of this CVE affecting a package published to Maven Central

9 cna-maven-package matched Queued for review CNA declares the affected component is a Maven artifact

10 known-cpe-product not-reached An NVD CPE naming a product ARMR tracks

11 cna-cpe-product not-reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

12 oracle-advisory-family not-reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

13 non-deployable-product not-reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

14 unmatched-product not-reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? cumulative: every rule gets a turn

15 patch-hint matched Mitigation candidate References include candidate fix URL (commit tier): https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c

16 open-source-maven skipped The affected package being open source on Maven, so the fix can be read

17 poc-derivable skipped An indexed exploit to reverse-engineer, where there is no source to read

18 no-exploit skipped With no fix path, a public exploit, or a CISA record of one

19 secure-rule-match no-match A vulnerability class already blocked by an ARMR security rule

20 below-action-threshold decided it matched No exploit published MEDIUM severity, no KEV listing, no public PoC clearing the evidence bar, no CISA exploitation finding, and not in an Oracle advisory — none of the signals we act on is present.

21 no-exploit-published skipped A published working exploit for this candidate, not only a proof of concept, a forecast, or nothing at all

Raw stored JSON document for this CVE ↗ · NVD ↗ · CVE.org ↗