{
  "threat_severity" : "Important",
  "public_date" : "2026-03-25T19:36:36Z",
  "bugzilla" : {
    "description" : "github.com/nats-io/nats-server: NATS-Server: Denial of Service via malformed WebSockets frame",
    "id" : "2451447",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2451447"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-1286",
  "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.", "A flaw was found in NATS-Server, a high-performance messaging system. A remote attacker can exploit this vulnerability before authentication by sending a specially crafted WebSockets frame. This missing sanity check can trigger a server panic, leading to a Denial of Service (DoS) for affected deployments that use WebSockets and expose the network port to untrusted endpoints." ],
  "package_state" : [ {
    "product_name" : "Multicluster Global Hub",
    "fix_state" : "Not affected",
    "package_name" : "multicluster-globalhub/multicluster-globalhub-grafana-rhel9",
    "cpe" : "cpe:/a:redhat:multicluster_globalhub"
  }, {
    "product_name" : "Red Hat OpenShift Container Platform 4",
    "fix_state" : "Not affected",
    "package_name" : "openshift4/oc-mirror-plugin-rhel9",
    "cpe" : "cpe:/a:redhat:openshift:4"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-27889\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-27889\nhttps://advisories.nats.io/CVE/secnote-2026-03.txt\nhttps://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6" ],
  "name" : "CVE-2026-27889",
  "mitigation" : {
    "value" : "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.",
    "lang" : "en:us"
  },
  "csaw" : false
}