{"id":"CVE-2026-42582","title":"Netty is an asynchronous, event-driven network application framework","summary":"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 byt…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-770","CWE-789"],"vendor":"netty","product":"netty","affected":["netty >= 4.2.0, < 4.2.13"],"patched":["netty 4.2.13"],"published":"2026-05-13","updated":"2026-07-10","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-42582","references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-2c5c-chwr-9hqw","label":"security-advisories@github.com"},{"url":"https://github.com/netty/netty/security/advisories/GHSA-2c5c-chwr-9hqw","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd"],"epss":0.00437,"epssPercentile":0.37442,"ingestedAt":"2026-07-10T16:05:09.791Z","slug":"CVE-2026-42582","body":"## Overview\n\nNetty 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.\n\n## Affected\n\n- `netty >= 4.2.0, < 4.2.13`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `netty 4.2.13`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}