{"id":"CVE-2026-58253","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-58253","generatedAt":"2026-10-28T02:11:38.107Z","title":"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…","description":"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.","published":"2026-07-08T20:16:55.000Z","lastModified":"2026-10-25T17:10:00.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L"},"cwe":["CWE-287"],"affected":["linuxfoundation/nats-server"],"epss":{"score":0.00368,"percentile":0.30481,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/nats-io/nats-server/commit/7b81dd455ea95960090a84858c7662827948d1b6","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/commit/8b8e1ad4ceed32321e00d4fc6e76be05bc13bca6","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/commit/b86147e81710a52b72a7f7275f91d69f723f5cb3","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.11.16","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.7","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.0","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-38x3-76xf-cq45","tags":["Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-58253","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}