{"id":"CVE-2026-59898","aliases":["GHSA-4mp9-239f-g9hg"],"url":"https://o3.security/vulnerability/CVE-2026-59898","summary":"Netty: WebSockets V07/V08 handshaker missing Connection/Upgrade validation","details":"Netty is an asynchronous, event-driven network application framework.  Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` / `Upgrade: websocket` headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.","published":"2026-07-29T18:02:07.415Z","modified":"2026-08-12T03:51:14.871759925Z","cvss":null,"epss":{"score":0.00249,"percentile":0.16191,"asOf":"2026-09-06"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http","fixedVersion":"4.2.16.Final"},{"ecosystem":"Maven","name":"io.netty:netty-codec-http","fixedVersion":"4.1.136.Final"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59898.json"},{"type":"ADVISORY","url":"https://github.com/netty/netty/security/advisories/GHSA-4mp9-239f-g9hg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59898"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:14.871759925Z"}}