{"cve":"CVE-2026-33871","nvd":{"published":"2026-03-27T20:16:34.833","modified":"2026-09-14T13:18:18.077","status":"Modified","description":"Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","score":8.7},"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-770"],"references":["https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv","https://access.redhat.com/errata/RHSA-2026:10175","https://access.redhat.com/errata/RHSA-2026:10184","https://access.redhat.com/errata/RHSA-2026:13571","https://access.redhat.com/errata/RHSA-2026:14272"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-33871","score":0.01145,"percentile":0.66751,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-w9fj-cfpg-grvv","url":"https://osv.dev/vulnerability/GHSA-w9fj-cfpg-grvv","summary":"Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass","modified":"2026-09-10T03:50:41.535305906Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","ranges":["<4.1.132.Final"],"fixed":["4.1.132.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","ranges":[">=4.2.0.Alpha1 <4.2.11.Final"],"fixed":["4.2.11.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."]}