CVE-2026-42585

Netty: HTTP Request Smuggling due to malformed Transfer-Encoding

HIGH

7.5

CVSS Score

Published: May 13, 2026 at 06:12 PM UTC

Updated: October 26, 2026 at 05:10 PM UTC

2 products affected across 2 vendorsNettyNetty

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Severity

HIGH7.5

Exploit prediction

EPSS 0.3%

SSVC

PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Netty · Nettymaven

95%

v < 4.1.1334.2.0 ≤ v < 4.2.13

Affected range stops below 4.1.133.Final, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.2.13.Final, so it looks safe — our inference, not a vendor statement

Netty · Io Netty

90%

v < 4.1.133.Final4.2.0.Alpha1 ≤ v < 4.2.13.Final

Affected range stops below 4.1.133.Final, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.2.13.Final, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://github.com/netty/netty/security/advisories/GHSA-38f8-5428-x5cv

References (1)

x_refsource_CONFIRMExploitVendor Advisory

Source: cverecord

https://github.com/netty/netty/security/advisories/GHSA-38f8-5428-x5cv

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-444

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