CVE-2026-42585

Netty: HTTP Request Smuggling due to malformed Transfer-Encoding

Published May 13, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-38f8-5428-x5cv Netty vulnerable to HTTP Request Smuggling due to malformed Transfer-Encoding
Ubuntu USN Ubuntu USN USN-8401-1 Netty vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Io.netty
Io.netty netty-codec-http
Netty
Netty netty
Vendors & Products Io.netty
Io.netty netty-codec-http
Netty
Netty netty
Type Values Removed Values Added
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.
Title Netty: HTTP Request Smuggling due to malformed Transfer-Encoding
Weaknesses CWE-444
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 15, 2026, 8:34 PM
Reserved
Apr 28, 2026, 5:26 PM
Status
Analyzed
Published
May 13, 2026, 7:17 PM
Modified
Oct 26, 2026, 5:10 PM
Severity
Moderate
Public date
May 13, 2026, 6:12 PM