{"id":"CVE-2026-33248","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-33248","generatedAt":"2026-10-28T00:07:58.732Z","title":"Prior to versions 2.11.15 and 2.12.6, when using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication…","description":"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, when using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypass. This does require a valid certificate from a CA already trusted for client certificates, and `DN` naming patterns which the NATS maintainers consider highly unlikely. So this is an unlikely attack. Nonetheless, administrators who have been very sophisticated in their `DN` construction patterns might conceivably be impacted. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, developers should review their CA issuing practices.","published":"2026-03-25T21:16:48.000Z","lastModified":"2026-06-17T10:37:11.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":4.2,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N"},"cwe":["CWE-287","CWE-295"],"affected":["linuxfoundation/nats-server"],"epss":{"score":0.00149,"percentile":0.04039,"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":"low","text":"Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://advisories.nats.io/CVE/secnote-2026-13.txt","tags":["Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-3f24-pcvm-5jqc","tags":["Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-33248","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."}