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NATS Server: Pre-auth server crash via double INFO in leafnode handshake

Type: advisorySources: OSV

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.12.8 and 2.11.17, an unauthenticated peer with network access to a leafnode listener with compression enabled could crash the server during the pre-authentication leafnode handshake by sending repeated leafnode INFO protocol messages before authentication and account setup completed. This issue is fixed in versions 2.12.8 and 2.11.17.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-58250
Confirmed fixed CVEs
Not specified
Updated in this feed
5 Nov 2026, 04:09 UTC · Revision 1

Source evidence

NATS Server: Pre-auth server crash via double INFO in leafnode handshake

core-osv · Original source

Published 8 Jul 2026, 19:48 UTC

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.12.8 and 2.11.17, an unauthenticated peer with network access to a leafnode listener with compression enabled could crash the server during the pre-authentication leafnode handshake by sending repeated leafnode INFO protocol messages before authentication and account setup completed. This issue is fixed in versions 2.12.8 and 2.11.17.

osv:CVE-2026-58250
Complete source record
{
  "id": "e66cea0b9c31f55147429c16ccc7560267de188c30c7a04323da2d2038e83956",
  "url": "https://osv.dev/vulnerability/CVE-2026-58250",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NATS Server: Pre-auth server crash via double INFO in leafnode handshake",
    "summary": "NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.12.8 and 2.11.17, an unauthenticated peer with network access to a leafnode listener with compression enabled could crash the server during the pre-authentication leafnode handshake by sending repeated leafnode INFO protocol messages before authentication and account setup completed. This issue is fixed in versions 2.12.8 and 2.11.17.",
    "evidence": "osv:CVE-2026-58250",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-58250",
      "aliases": [
        "BIT-nats-2026-58250",
        "CVE-2026-58250",
        "GHSA-3g5q-cfh2-cq67"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nats-io/nats-server",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0f192db71455eaca7f1fef14548a239845f24b96"
                },
                {
                  "introduced": "fc6ec648d806652d282d2f0edb6cb9f22c895572"
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                {
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                },
                {
                  "fixed": "8dcb26eaea78fdcbe96dbee5986d6019fd5cb94a"
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                {
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                }
              ],
              "database_specific": {
                "extracted_events": [
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                    "cpe": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
                    "range": [
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                    "source": "CPE_RANGE"
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                    "cpe": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*",
                    "range": [
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                    "source": "CPE_RANGE"
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                    "range": [
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                    "source": "REFERENCES_COMMIT"
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                    "source": "REFERENCES_COMMIT"
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                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.11.17"
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                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.12.8"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58250.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:42.403560008Z",
      "provider": "osv",
      "references": [
        "https://github.com/nats-io/nats-server/releases/tag/v2.11.17",
        "https://github.com/nats-io/nats-server/releases/tag/v2.12.8",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58250.json",
        "https://github.com/nats-io/nats-server/security/advisories/GHSA-3g5q-cfh2-cq67",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-58250",
        "https://github.com/nats-io/nats-server/commit/8dcb26eaea78fdcbe96dbee5986d6019fd5cb94a",
        "https://github.com/nats-io/nats-server/commit/fc5fe39177533e9dbdd651d2458285bfae1dde27"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-476"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58250.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-58250",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510163,
  "published_at": "2026-07-08T19:48:55.058+00:00"
}