{"id":"CVE-2026-12151","aliases":["GHSA-vxpw-j846-p89q"],"url":"https://o3.security/vulnerability/CVE-2026-12151","summary":"undici WebSocket client vulnerable to denial of service via fragment count bypass","details":"Impact:\nThe undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service.\n\nAffected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.\n\nAll releases starting at undici 6.17.0 are affected.\n\nPatches: Upgrade to undici >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds:\nNo workaround is available. The fix must be applied through an upgrade.","published":"2026-06-17T16:05:38.785Z","modified":"2026-08-12T03:51:28.369945813Z","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":{"score":0.00789,"percentile":0.52981,"asOf":"2026-08-12"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"undici","fixedVersion":"6.27.0"},{"ecosystem":"npm","name":"undici","fixedVersion":"7.28.0"},{"ecosystem":"npm","name":"undici","fixedVersion":"8.5.0"}],"fix":null,"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12151.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:34342"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:35841"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:35842"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:35891"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:35892"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:36621"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:36754"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:36820"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:38009"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:38236"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:39246"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:39868"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:41929"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:41947"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:47728"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:48124"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:48151"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:52399"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-12151"},{"type":"ADVISORY","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12151.json"},{"type":"ADVISORY","url":"https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-12151"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2489980"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:28.369945813Z"}}