nats-server — security advisory

{
  "id": "9495808f898fa7c3e805c50110a62ca2733a2bc5a2630843f6bb9d5c85fa3389",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-33246",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-33246",
    "summary": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The 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. A 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. Prior to versions 2.11.15 and 2.12.6, NATS clients relying upon the Nats-Request-Info: header could be spoofed. This does 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. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.",
    "evidence": "osv:UBUNTU-CVE-2026-33246",
    "products": [
      {
        "name": {
          "value": "nats-server",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.9.19-1build1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.10.3-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.10.4-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.10.7-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.10.7-1ubuntu0.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.10.7-1ubuntu0.2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.10.7-1ubuntu0.3",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "nats-server",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.10.24-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.10.27-1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "nats-server",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.10.27-1build1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.14.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "2.14.3-1",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "nats-server",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.10.27-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.10.27-1build1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "2.10.27-1ubuntu0.26.04.1~esm1",
            "evidence": "/affected/3/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2026-33246",
      "aliases": [
        "UBUNTU-CVE-2026-33246"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"
        },
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "nats-server",
            "purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "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"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33246.json"
          },
          "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"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "nats-server",
            "purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "2.10.24-1",
            "2.10.27-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33246.json"
          },
          "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"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "nats-server",
            "purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "2.10.27-1build1",
            "2.14.1-1",
            "2.14.3-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33246.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "golang-github-nats-io-nats-server-dev",
                "binary_version": "2.14.3-1"
              },
              {
                "binary_name": "nats-server",
                "binary_version": "2.14.3-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "nats-server",
            "purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=esm-apps%2Fresolute",
            "ecosystem": "Ubuntu:Pro:26.04:LTS"
          },
          "versions": [
            "2.10.27-1",
            "2.10.27-1build1",
            "2.10.27-1ubuntu0.26.04.1~esm1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33246.json"
          },
          "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"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:59:59.781786628Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-33246"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-33246",
        "https://www.cve.org/CVERecord?id=CVE-2026-33246",
        "https://advisories.nats.io/CVE/secnote-2026-08.txt",
        "https://github.com/nats-io/nats-server/security/advisories/GHSA-55h8-8g96-x4hj"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-33246",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 360087,
  "published_at": "2026-03-25T20:16:00+00:00"
}