{"cve":"CVE-2026-42578","nvd":{"published":"2026-05-13T19:17:23.210","modified":"2026-09-18T13:18:18.427","status":"Modified","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.","cvss_v4":{"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","score":2.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-113","CWE-93"],"references":["https://github.com/netty/netty/security/advisories/GHSA-45q3-82m4-75jr","https://access.redhat.com/errata/RHSA-2026:23808","https://access.redhat.com/errata/RHSA-2026:24502","https://access.redhat.com/errata/RHSA-2026:25123","https://access.redhat.com/errata/RHSA-2026:28010"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:35:16.954578616+00:00"},"epss":{"cve":"CVE-2026-42578","score":0.01065,"percentile":0.64698,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-45q3-82m4-75jr","url":"https://osv.dev/vulnerability/GHSA-45q3-82m4-75jr","summary":"Netty has HTTP Header Injection via HttpProxyHandler Disabled Validation (Incomplete Fix CVE-2025-67735)","modified":"2026-09-10T03:51:04.662453637Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-handler-proxy","purl":"pkg:maven/io.netty/netty-handler-proxy","ranges":["<4.1.133.Final"],"fixed":["4.1.133.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-handler-proxy","purl":"pkg:maven/io.netty/netty-handler-proxy","ranges":[">=4.2.0.Alpha1 <4.2.13.Final"],"fixed":["4.2.13.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}