Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | < 4.2.13 |
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/security/advisories/GHSA-2c5c-chwr-9hqwExploitVendor Advisory
- https://github.com/netty/netty/security/advisories/GHSA-2c5c-chwr-9hqwExploitVendor Advisory
FAQ
What is CVE-2026-42582?
CVE-2026-42582 is a vulnerability with a CVSS score of 7.5 (HIGH). 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#decodeHuff...
How severe is CVE-2026-42582?
CVE-2026-42582 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-42582?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.