CVE Vulnerabilities

CVE-2025-67735

Improper Neutralization of CRLF Sequences ('CRLF Injection')

Published: Dec 16, 2025 | Modified: Jan 02, 2026
CVSS 3.x
N/A
Source:
NVD
CVSS 2.x
RedHat/V2
RedHat/V3
6.5 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Ubuntu
MEDIUM

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.129.Final and 4.2.8.Final, the io.netty.handler.codec.http.HttpRequestEncoder has a CRLF injection with the request URI when constructing a request. This leads to request smuggling when HttpRequestEncoder is used without proper sanitization of the URI. Any application / framework using HttpRequestEncoder can be subject to be abused to perform request smuggling using CRLF injection. Versions 4.1.129.Final and 4.2.8.Final fix the issue.

Weakness

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

Affected Software

Name Vendor Start Version End Version
Netty Netty * 4.1.129 (excluding)
Netty Netty 4.2.0 (including) 4.2.8 (excluding)

Potential Mitigations

References