{"id":"CVE-2026-27889","summary":"NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead","details":"NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.2.0 and prior to versions 2.11.14 and 2.12.5, a missing sanity check on a WebSockets frame could trigger a server panic in the nats-server.  This happens before authentication, and so is exposed to anyone who can connect to the websockets port. Versions 2.11.14 and 2.12.5 contains a fix. A workaround is available. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points. If one is able to do so, a defense in depth of restricting either of these will mitigate the attack.","aliases":["BIT-nats-2026-27889","GHSA-pq2q-rcw4-3hr6","GO-2026-4841"],"modified":"2026-04-10T05:37:29.445547Z","published":"2026-03-25T19:36:36.370Z","related":["CGA-x45q-fj2h-xjrc","SUSE-SU-2026:1135-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-190"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27889.json"},"references":[{"type":"ADVISORY","url":"https://advisories.nats.io/CVE/secnote-2026-03.txt"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27889.json"},{"type":"ADVISORY","url":"https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27889"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nats-io/nats-server","events":[{"introduced":"0e3c7230e4b7c85795592f74a62351f6fe22fcbd"},{"fixed":"797d2514fdb29ccb2b654f7fefbcb166ccb66cf1"}],"database_specific":{"versions":[{"introduced":"2.2.0"},{"fixed":"2.11.14"}]}},{"type":"GIT","repo":"https://github.com/nats-io/nats-server","events":[{"introduced":"fc6ec648d806652d282d2f0edb6cb9f22c895572"},{"fixed":"0f6c831ec1df25bc3dc81d25faae0ed0bac15a96"}],"database_specific":{"versions":[{"introduced":"2.12.0"},{"fixed":"2.12.5"}]}}],"versions":["v2.10.0","v2.10.1","v2.10.2","v2.10.3","v2.11.0","v2.11.0-RC.1","v2.11.0-RC.2","v2.11.0-RC.3","v2.11.0-RC.4","v2.11.0-RC.5","v2.11.10","v2.11.10-RC.1","v2.11.11","v2.11.11-RC.1","v2.11.11-RC.2","v2.11.11-RC.3","v2.11.11-RC.4","v2.11.12","v2.11.12-RC.1","v2.11.12-RC.2","v2.11.12-RC.3","v2.11.12-RC.4","v2.11.12-RC.5","v2.11.12-RC.6","v2.11.12-RC.7","v2.11.2","v2.11.2-RC.1","v2.11.2-RC.2","v2.11.2-RC.3","v2.11.3","v2.11.3-RC.1","v2.11.3-RC.2","v2.11.4","v2.11.4-RC.1","v2.11.4-RC.2","v2.11.4-RC.3","v2.11.5","v2.11.5-RC.1","v2.11.5-RC.2","v2.11.5-RC.3","v2.11.5-RC.4","v2.11.6","v2.11.6-RC.1","v2.11.7","v2.11.7-RC.1","v2.11.7-RC.2","v2.11.7-RC.3","v2.11.8","v2.11.8-RC.1","v2.11.9","v2.11.9-RC.1","v2.11.9-RC.2","v2.11.9-RC.3","v2.12.0","v2.12.1","v2.12.1-RC.1","v2.12.1-RC.2","v2.12.1-RC.3","v2.12.1-RC.4","v2.12.1-RC.5","v2.12.2","v2.12.2-RC.1","v2.12.2-RC.2","v2.12.2-RC.3","v2.12.2-RC.4","v2.12.3","v2.12.3-RC.1","v2.12.3-RC.2","v2.12.3-RC.3","v2.12.3-RC.4","v2.12.3-RC.5","v2.12.4","v2.12.4-RC.1","v2.12.4-RC.2","v2.12.4-RC.3","v2.12.4-RC.4","v2.12.4-RC.5","v2.12.4-RC.6","v2.12.5-RC.1","v2.12.5-RC.2","v2.2.0","v2.2.1","v2.2.2","v2.2.3","v2.2.4","v2.2.5","v2.2.6","v2.3.0","v2.3.1","v2.3.2","v2.3.3","v2.3.4","v2.4.0","v2.5.0","v2.6.0","v2.6.1","v2.6.2","v2.6.3","v2.6.4","v2.6.5","v2.6.6","v2.7.0","v2.7.0-rc1","v2.7.0-rc2","v2.7.1","v2.7.2","v2.7.3","v2.7.4","v2.8.0","v2.8.1","v2.8.2","v2.8.3","v2.8.4","v2.9.0","v2.9.1","v2.9.10","v2.9.11","v2.9.12","v2.9.14","v2.9.15","v2.9.16","v2.9.17","v2.9.18","v2.9.19","v2.9.2","v2.9.20","v2.9.21","v2.9.22","v2.9.3","v2.9.4","v2.9.5","v2.9.6","v2.9.7","v2.9.8","v2.9.9"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27889.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}