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Medium

NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing

Type: advisorySources: OSV

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-33223
Confirmed fixed CVEs
Not specified
Updated in this feed
5 Nov 2026, 01:03 UTC · Revision 1

Source evidence

NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing

core-osv · Original source

Published 25 Mar 2026, 20:20 UTC

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

osv:CVE-2026-33223
Complete source record
{
  "id": "0b00d5c512e29cef7de8d7ff7eb6e92174e2b7282245571dcd572533ab5564b9",
  "url": "https://osv.dev/vulnerability/CVE-2026-33223",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing",
    "summary": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.",
    "evidence": "osv:CVE-2026-33223",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-33223",
      "aliases": [
        "BIT-nats-2026-33223",
        "CVE-2026-33223",
        "GHSA-pwx7-fx9r-hr4h",
        "GO-2026-4835"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nats-io/nats-server",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "bef17e1d9de6574fae0eabe1798db0d4529834e4"
                },
                {
                  "introduced": "fc6ec648d806652d282d2f0edb6cb9f22c895572"
                },
                {
                  "fixed": "0e0639058e0d2d8fce0cc34941f9897da152ab32"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.11.15"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.12.0"
                      },
                      {
                        "fixed": "2.12.6"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.12.4",
            "v2.11.14",
            "v2.12.5",
            "v2.11.12",
            "v2.12.5-RC.2",
            "v2.12.5-RC.1",
            "v2.11.12-RC.7",
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            "v2.11.12-RC.6",
            "v2.12.4-RC.5",
            "v2.11.12-RC.5",
            "v2.12.4-RC.4",
            "v2.12.2",
            "v2.11.12-RC.4",
            "v2.12.4-RC.3",
            "v2.12.4-RC.2",
            "v2.11.12-RC.3",
            "v2.12.4-RC.1",
            "v2.11.12-RC.2",
            "v2.12.3",
            "v2.11.12-RC.1",
            "v2.11.11",
            "v2.12.3-RC.5",
            "v2.12.3-RC.4",
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            "v2.12.3-RC.2",
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            "v2.12.2-RC.4",
            "v2.11.11-RC.4",
            "v2.12.2-RC.3",
            "v2.11.11-RC.3",
            "v2.12.1",
            "v2.12.2-RC.2",
            "v2.11.11-RC.2",
            "v2.11.11-RC.1",
            "v2.12.2-RC.1",
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            "v2.12.1-RC.4",
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            "v2.12.1-RC.2",
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            "v2.11.10-RC.1",
            "v2.11.9",
            "v2.11.9-RC.3",
            "v2.11.9-RC.2",
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            "v2.11.8",
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            "v2.11.7-RC.3",
            "v2.11.7-RC.2",
            "v2.11.7-RC.1",
            "v2.11.6",
            "v2.11.6-RC.1",
            "v2.11.5",
            "v2.11.5-RC.4",
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            "v2.11.5-RC.1",
            "v2.11.4",
            "v2.11.4-RC.3",
            "v2.11.4-RC.2",
            "v2.11.4-RC.1",
            "v2.11.3",
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            "v2.11.0-RC.3",
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            "v2.11.0-RC.1",
            "v2.10.3",
            "v2.10.2",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33223.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.292534427Z",
      "provider": "osv",
      "references": [
        "https://advisories.nats.io/CVE/secnote-2026-09.txt",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33223.json",
        "https://github.com/nats-io/nats-server/security/advisories/GHSA-pwx7-fx9r-hr4h",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-33223"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-290"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33223.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-33223",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 508881,
  "published_at": "2026-03-25T20:20:00.158+00:00"
}