Netty’s HttpObjectDecoder skips arbitrary initial control characters when only initial CRLF characters are permitted_CVE-2026-50020

{
    "lastseen": "",
    "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\u20130x1F and 0x7F) as well as all whitespace. RFC 9112 \u00a72.2 only asks servers to ignore empty CRLF lines preceding the request-line \u2014 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.",
    "published": "2026-06-12T14:55:32.165Z",
    "modified": "2026-06-12T14:55:32.165Z",
    "type": "cve",
    "title": "Netty's HttpObjectDecoder skips arbitrary initial control characters when only initial CRLF characters are permitted",
    "source": "GitHub_M",
    "references": "https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c\nhttps://github.com/netty/netty/releases/tag/netty-4.1.135.Final\nhttps://github.com/netty/netty/releases/tag/netty-4.2.15.Final",
    "id": "CVE-2026-50020",
    "bulletinFamily": "",
    "cwe": [
        "CWE-444"
    ],
    "cvelist": null,
    "sourceData": "netty netty >= 4.2.0.Final, < 4.2.15.Final\nnetty netty < 4.1.135.Final",
    "sourceHref": "",
    "cvss": {
        "score": 5.3,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "netty",
    "version": ">= 4.2.0.Final, < 4.2.15.Final",
    "vendor": "netty",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}