CVE-2026-42578

Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation

Published May 13, 2026 CVSS 4.0 · 2.9 Low EPSS 1.1% 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's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. 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

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-45q3-82m4-75jr Netty has HTTP Header Injection via HttpProxyHandler Disabled Validation (Incomplete Fix CVE-2025-67735)
Ubuntu USN Ubuntu USN USN-8401-1 Netty vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
CPEs cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

Type Values Removed Values Added
First Time appeared Netty
Netty netty
Vendors & Products 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's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
Title Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation
Weaknesses CWE-113
References
Metrics cvssV4_0

{'score': 2.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 18, 2026, 12:04 PM
Reserved
Apr 28, 2026, 5:26 PM
Status
Modified
Published
May 13, 2026, 7:17 PM
Modified
Nov 11, 2026, 8:10 PM
Severity
Important
Public date
May 13, 2026, 5:57 PM