{"id":"JLSEC-2026-1153","details":"NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, when `no_auth_user` was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication and operate with the privileges associated with that connection type. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.","modified":"2026-08-03T19:15:08.701683517Z","published":"2026-08-03T19:08:57.739Z","upstream":["CVE-2026-58253"],"database_specific":{"license":"CC-BY-4.0","sources":[{"published":"2026-07-08T20:16:54.943Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-58253","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58253","database_specific":{"status":"Analyzed"},"id":"CVE-2026-58253","imported":"2026-08-03T18:16:27.685Z","modified":"2026-07-13T15:25:44.430Z"}]},"references":[{"type":"WEB","url":"https://github.com/nats-io/nats-server/commit/7b81dd455ea95960090a84858c7662827948d1b6"},{"type":"WEB","url":"https://github.com/nats-io/nats-server/commit/8b8e1ad4ceed32321e00d4fc6e76be05bc13bca6"},{"type":"WEB","url":"https://github.com/nats-io/nats-server/commit/b86147e81710a52b72a7f7275f91d69f723f5cb3"},{"type":"WEB","url":"https://github.com/nats-io/nats-server/releases/tag/v2.11.16"},{"type":"WEB","url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.7"},{"type":"WEB","url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.0"},{"type":"WEB","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-38x3-76xf-cq45"}],"affected":[{"package":{"name":"nats_server_jll","ecosystem":"Julia","purl":"pkg:julia/nats_server_jll?uuid=8b1691f7-6002-537d-bdf7-c6203599dc08"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.14.3+0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-1153.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L"}]}