{"schema_version":"1.9.0","id":"GHSA-55h8-8g96-x4hj","published":"2026-03-24T21:50:25Z","modified":"2026-09-10T03:50:59.829737231Z","aliases":["BIT-nats-2026-33246","CVE-2026-33246","GO-2026-4830"],"summary":"NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers","details":"### Background\n\nNATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing.\n\nThe nats-server allows hub/spoke topologies using \"leafnode\" connections by other nats-servers.  NATS messages can have headers.\n\n### Problem Description\n\nThe nats-server offers a `Nats-Request-Info:` message header, providing information about a request.  This is supposed to provide enough information to allow for account/user identification, such that NATS clients could make their own decisions on how to trust a message, provided that they trust the nats-server as a broker.\n\nA leafnode connecting to a nats-server is not fully trusted unless the system account is bridged too.  Thus identity claims should not have propagated unchecked.\n\nThus NATS clients relying upon the Nats-Request-Info: header could be spoofed.\n\nDoes not directly affect the nats-server itself, but the CVSS Confidentiality and Integrity scores are based upon what a hypothetical client might choose to do with this NATS header.\n\n### Affected Versions\n\nAny version before v2.12.6 or v2.11.15\n\n### Workarounds\n\nNone.","affected":[{"package":{"name":"github.com/nats-io/nats-server/v2","ecosystem":"Go","purl":"pkg:golang/github.com/nats-io/nats-server/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.11.15"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-55h8-8g96-x4hj/GHSA-55h8-8g96-x4hj.json"}},{"package":{"name":"github.com/nats-io/nats-server/v2","ecosystem":"Go","purl":"pkg:golang/github.com/nats-io/nats-server/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.12.0-RC.1"},{"fixed":"2.12.6"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-55h8-8g96-x4hj/GHSA-55h8-8g96-x4hj.json"}},{"package":{"name":"github.com/nats-io/nats-server","ecosystem":"Go","purl":"pkg:golang/github.com/nats-io/nats-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-55h8-8g96-x4hj/GHSA-55h8-8g96-x4hj.json"}}],"references":[{"type":"WEB","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-55h8-8g96-x4hj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33246"},{"type":"WEB","url":"https://advisories.nats.io/CVE/secnote-2026-08.txt"},{"type":"PACKAGE","url":"https://github.com/nats-io/nats-server"}],"database_specific":{"cwe_ids":["CWE-287","CWE-290"],"github_reviewed":true,"github_reviewed_at":"2026-03-24T21:50:25Z","nvd_published_at":"2026-03-25T20:16:33Z","severity":"MODERATE"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"}]}