UBUNTU-CVE-2026-27889 (CVE-2026-27889)

Vulnerability from osv_ubuntu – Published: 2026-03-25 20:16 – Updated: 2026-07-02 16:11 – Source website
VLAI
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.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-nats-io-nats-server-dev",
            "binary_version": "2.10.7-1ubuntu0.3"
          },
          {
            "binary_name": "nats-server",
            "binary_version": "2.10.7-1ubuntu0.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "nats-server",
        "purl": "pkg:deb/ubuntu/nats-server@2.10.7-1ubuntu0.3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.9.19-1build1",
        "2.10.3-1",
        "2.10.4-1",
        "2.10.7-1",
        "2.10.7-1ubuntu0.1",
        "2.10.7-1ubuntu0.2",
        "2.10.7-1ubuntu0.3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-nats-io-nats-server-dev",
            "binary_version": "2.10.27-1"
          },
          {
            "binary_name": "nats-server",
            "binary_version": "2.10.27-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "nats-server",
        "purl": "pkg:deb/ubuntu/nats-server@2.10.27-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.10.24-1",
        "2.10.27-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "golang-github-nats-io-nats-server-dev",
            "binary_version": "2.10.27-1ubuntu0.26.04.1~esm1"
          },
          {
            "binary_name": "nats-server",
            "binary_version": "2.10.27-1ubuntu0.26.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "nats-server",
        "purl": "pkg:deb/ubuntu/nats-server@2.10.27-1ubuntu0.26.04.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.10.27-1",
        "2.10.27-1build1",
        "2.10.27-1ubuntu0.26.04.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "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.",
  "id": "UBUNTU-CVE-2026-27889",
  "modified": "2026-07-02T16:11:59Z",
  "published": "2026-03-25T20:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-27889"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27889"
    },
    {
      "type": "REPORT",
      "url": "https://advisories.nats.io/CVE/secnote-2026-03.txt"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-27889"
  ]
}



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