CVE-2026-42578 Details
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.
A vulnerability exists in Netty's HttpProxyHandler component, specifically in versions through 4.2.12.Final and 4.1.132.Final. The issue arises because the HttpProxyHandler constructs HTTP CONNECT requests with header validation disabled, allowing for HTTP header injection. This vulnerability can be exploited by manipulating outbound headers, which are sent to the proxy server without proper validation. The flaw is a regression of a previously addressed CRLF injection vulnerability, now reintroduced by the same component.
Users can upgrade to Netty versions 4.2.13.Final or 4.1.133.Final, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 13, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-113 | Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') | [email protected] |
| CWE-93 | Improper Neutralization of CRLF Sequences ('CRLF Injection') | redhat-SADP |
Affected Products
| Product | Versions |
|---|---|
| netty netty | < 4.1.133 >= 4.2.0, < 4.2.13 |
CPE
Remediation
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Change History
19 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 18, 2026 | CVE Modified | redhat-SADP |
| Sep 17, 2026 | CVE Modified | redhat-SADP |
| Sep 11, 2026 | CVE Modified | redhat-SADP |
| Sep 9, 2026 | CVE Modified | redhat-SADP |
| Sep 7, 2026 | CVE Modified | [email protected] |
| Sep 7, 2026 | CVE Modified | redhat-SADP |
| Sep 7, 2026 | CVE Modified | CISA-ADP |
| Aug 13, 2026 | CVE Modified | redhat-SADP |
| Aug 12, 2026 | CVE Modified | redhat-SADP |
| Jul 21, 2026 | CVE Modified | redhat-SADP |
| Jul 15, 2026 | CVE Modified | redhat-SADP |
| Jul 10, 2026 | CVE Modified | redhat-SADP |
| Jul 9, 2026 | CVE Modified | redhat-SADP |
| Jun 30, 2026 | CVE Modified | redhat-SADP |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 17, 2026 | CVE Modified | [email protected] |
| May 18, 2026 | Initial Analysis | [email protected] |
| May 13, 2026 | CVE Modified | CISA-ADP |
| May 13, 2026 | New CVE Received | [email protected] |