{"cve":"CVE-2026-56816","nvd":{"published":"2026-07-21T22:17:14.803","modified":"2026-08-07T20:47:16.297","status":"Analyzed","description":"Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's `Http3FrameCodec` buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; `decodeFrame` trusts `payLoadLength`, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-400"],"references":["https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b","https://github.com/netty/netty/releases/tag/netty-4.2.16.Final","https://github.com/netty/netty/security/advisories/GHSA-hpcc-26xq-25fv"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:45:53.305392138+00:00"},"epss":{"cve":"CVE-2026-56816","score":0.00644,"percentile":0.50875,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-hpcc-26xq-25fv","url":"https://osv.dev/vulnerability/GHSA-hpcc-26xq-25fv","summary":"Netty: Memory Exhaustion via HTTP/3 Reserved Frame Types","modified":"2026-09-10T03:51:11.620299875Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http3","purl":"pkg:maven/io.netty/netty-codec-http3","ranges":["<4.2.16.Final"],"fixed":["4.2.16.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}