{"cve":"CVE-2026-50020","nvd":{"published":"2026-06-12T16:16:31.447","modified":"2026-06-17T10:57:35.237","status":"Analyzed","description":"Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, `HttpObjectDecoder` skips every byte for which `Character.isISOControl(b)` is `true` (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-444"],"references":["https://github.com/netty/netty/releases/tag/netty-4.1.135.Final","https://github.com/netty/netty/releases/tag/netty-4.2.15.Final","https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c","https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-50020","score":0.00232,"percentile":0.1417,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-hvcg-qmg6-jm4c","url":"https://osv.dev/vulnerability/GHSA-hvcg-qmg6-jm4c","summary":"Netty: HttpObjectDecoder skips arbitrary initial control characters when only initial CRLF characters are permitted","modified":"2026-09-10T03:50:50.025404342Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http","purl":"pkg:maven/io.netty/netty-codec-http","ranges":[">=4.2.0.Final <4.2.15.Final"],"fixed":["4.2.15.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-codec-http","purl":"pkg:maven/io.netty/netty-codec-http","ranges":["<4.1.135.Final"],"fixed":["4.1.135.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."]}