{"id":"ALPINE-CVE-2026-33248","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, 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.","modified":"2026-11-03T06:33:02.414239660Z","published":"2026-03-25T21:16:47.563Z","upstream":["CVE-2026-33248"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2026-33248"}],"affected":[{"package":{"name":"nats-server","ecosystem":"Alpine:v3.23","purl":"pkg:apk/alpine/nats-server?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.12.0"},{"fixed":"2.12.6-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33248.json"}},{"package":{"name":"nats-server","ecosystem":"Alpine:v3.24","purl":"pkg:apk/alpine/nats-server?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.12.0"},{"fixed":"2.12.6-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-33248.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N"}]}