CVE-2026-42581

5.8 MEDIUM
Published: May 13, 2026 Modified: May 18, 2026
View on NVD

Description

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9
Source: security-advisories@github.com
Exploit Vendor Advisory Mitigation
https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Vendor Advisory Mitigation

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.8 / 10.0
EPSS (Exploit Probability)
0.4%
32th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

netty