{"id":"CVE-2026-33218","aliases":["BIT-nats-2026-33218","GHSA-vprv-35vv-q339","GO-2026-4837"],"url":"https://o3.security/vulnerability/CVE-2026-33218","summary":"NATS has pre-auth server panic via leafnode handling","details":"NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.","published":"2026-03-25T19:53:12.075Z","modified":"2026-09-11T03:30:24.352686443Z","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":"Go","name":"github.com/nats-io/nats-server/v2","fixedVersion":"2.11.15"},{"ecosystem":"Go","name":"github.com/nats-io/nats-server/v2","fixedVersion":"2.12.6"},{"ecosystem":"Go","name":"github.com/nats-io/nats-server","fixedVersion":null}],"fix":null,"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33218.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:21769"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:22347"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:23345"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-33218"},{"type":"ADVISORY","url":"https://advisories.nats.io/CVE/secnote-2026-10.txt"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33218.json"},{"type":"ADVISORY","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33218"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2451450"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:30:24.352686443Z"}}