{"id":"CVE-2026-42582","aliases":["GHSA-2c5c-chwr-9hqw"],"url":"https://o3.security/vulnerability/CVE-2026-42582","summary":"Netty: HTTP/3 QPACK literal unbounded allocation","details":"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.","published":"2026-05-13T18:06:55.559Z","modified":"2026-08-12T03:51:21.112458416Z","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"},"epss":{"score":0.00437,"percentile":0.37271,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http3","fixedVersion":"4.2.13.Final"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42582.json"},{"type":"ADVISORY","url":"https://github.com/netty/netty/security/advisories/GHSA-2c5c-chwr-9hqw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42582"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:21.112458416Z"}}