CVE-2026-42582: Netty

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Netty Netty: from 4.2.0, before 4.2.13 (fixed in 4.2.13)

Published 2026-05-13. Last modified 2026-07-10.