CVE-2026-42582

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final, when decoding header blocks, the non-Huffman branch of io.netty.handler.codec.http3.QpackDecoder#decodeHuffmanEncodedLiteral may execute new byte[length] for a string literal before verifying that length bytes are actually present in the compressed field section. The wire encoding allows a very large length to be expressed in few bytes. There is no check that length <= in.readableBytes() before new byte[length]. This vulnerability is fixed in 4.2.13.Final.

Database specific

{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42582.json",
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-770",
        "CWE-789"
    ]
}

References

Affected packages

Git / github.com/netty/netty

Affected ranges

Type

GIT

Repo

https://github.com/netty/netty

Events

Introduced

5451fbb0effd8460f57013bb33aefeb953144ed9

Fixed

b3844c8108b42f68d56144b36d4d1ed96078a688

Database specific

{
    "cpe": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "4.2.0.Alpha1"
        },
        {
            "fixed": "4.2.13.Final"
        },
        {
            "introduced": "0"
        },
        {
            "fixed": "4.2.13"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ]
}

Affected versions

netty-4.*

netty-4.2.0.Alpha1

netty-4.2.0.Alpha2

netty-4.2.0.Alpha3

netty-4.2.0.Alpha4

netty-4.2.0.Alpha5

netty-4.2.0.Beta1

netty-4.2.0.Final

netty-4.2.0.RC1

netty-4.2.0.RC2

netty-4.2.0.RC3

netty-4.2.0.RC4

netty-4.2.1.Final

netty-4.2.10.Final

netty-4.2.11.Final

netty-4.2.12.Final

netty-4.2.2.Final

netty-4.2.3.Final

netty-4.2.4.Final

netty-4.2.5.Final

netty-4.2.6.Final

netty-4.2.7.Final

netty-4.2.8.Final

netty-4.2.9.Final

Database specific

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-42582.json"