{"id":"CVE-2021-3859","aliases":["GHSA-339q-62wm-c39w"],"url":"https://o3.security/vulnerability/CVE-2021-3859","summary":"Undertow vulnerable to Denial of Service (DoS) attacks","details":"A flaw was found in Undertow that tripped the client-side invocation timeout with certain calls made over HTTP2. This flaw allows an attacker to carry out denial of service attacks.","published":"2022-08-26T16:15:09.623Z","modified":"2026-07-08T22:13:58.788374Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.undertow:undertow-core","fixedVersion":"2.2.15"}],"fix":{"url":"https://github.com/undertow-io/undertow/commit/e43f0ada3f4da6e8579e0020cec3cb1a81e487c2","label":"undertow-io/undertow@e43f0ad"},"references":[{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2021-3859"},{"type":"ADVISORY","url":"https://github.com/undertow-io/undertow/pull/1296"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20221201-0004/"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2010378"},{"type":"FIX","url":"https://github.com/undertow-io/undertow/commit/e43f0ada3f4da6e8579e0020cec3cb1a81e487c2"},{"type":"FIX","url":"https://issues.redhat.com/browse/UNDERTOW-1979"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T22:13:58.788374Z"}}