CVE-2026-42581

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpObjectDecoder strips a conflicting Content-Length header when a request carries both Transfer-Encoding: chunked and Content-Length, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving Content-Length intact in the forwarded HttpMessage. Any downstream proxy or handler that trusts Content-Length over Transfer-Encoding will disagree on message boundaries, enabling request smuggling. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS v3 5.8 MEDIUM

5.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9	Exploit Vendor Advisory Mitigation
https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9	Exploit Vendor Advisory Mitigation

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:netty:netty::::::::
	cpe:2.3:a:netty:netty::::::::

History

18 May 2026, 13:14

Type	Values Removed	Values Added
References	~~() https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9 -~~	() https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9 - Exploit, Vendor Advisory, Mitigation
CPE		cpe:2.3:a:netty:netty::::::::
First Time		Netty netty Netty

13 May 2026, 19:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-13 19:17

Updated : 2026-05-18 13:14

NVD link : CVE-2026-42581

Mitre link : CVE-2026-42581

CVE.ORG link : CVE-2026-42581

JSON object : View

Products Affected

netty

netty

CWE

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

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