Netty: SNI handler pre-allocates up to 16 MiB from nine attacker bytes_CVE-2026-45416

{
    "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, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.",
    "published": "2026-06-12T14:10:05.585Z",
    "modified": "2026-06-12T15:07:07.365Z",
    "type": "cve",
    "title": "Netty: SNI handler pre-allocates up to 16 MiB from nine attacker bytes",
    "source": "GitHub_M",
    "references": "https://github.com/netty/netty/security/advisories/GHSA-x4gw-5cx5-pgmh\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-2026-45416",
    "bulletinFamily": "",
    "cwe": [
        "CWE-770"
    ],
    "cvelist": null,
    "sourceData": "netty netty >= 4.2.0.Final, < 4.2.15.Final\nnetty netty < 4.1.135.Final",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
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            "privilegesRequired": "",
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            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "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
}