Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-03-27 11:47

Modified

2026-03-27 12:16

Summary

NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead

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.

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "nats",
        "purl": "pkg:bitnami/nats"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.2.0"
            },
            {
              "fixed": "2.11.14"
            },
            {
              "introduced": "2.12.0"
            },
            {
              "fixed": "2.12.5"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27889"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:nats:nats_server:*:*:*:*:*:go:*:*"
    ],
    "severity": "High"
  },
  "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": "BIT-nats-2026-27889",
  "modified": "2026-03-27T12:16:52.978Z",
  "published": "2026-03-27T11:47:22.988Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://advisories.nats.io/CVE/secnote-2026-03.txt"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27889"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead"
}

CVE-2026-27889 (GCVE-0-2026-27889)

Vulnerability from cvelistv5 – Published: 2026-03-25 19:36 – Updated: 2026-03-25 20:06

Title

NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead

Summary

Severity ?

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-190 - Integer Overflow or Wraparound

Assigner

GitHub_M

References

URL

Tags

	https://github.com/nats-io/nats-server/security/a…	x_refsource_CONFIRM
	https://advisories.nats.io/CVE/secnote-2026-03.txt	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	nats-io	nats-server	Affected: >= 2.2.0, < 2.11.14 Affected: >= 2.12.0, < 2.12.5

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27889",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-25T20:06:22.827675Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-25T20:06:31.897Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nats-server",
          "vendor": "nats-io",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.2.0, \u003c 2.11.14"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.12.0, \u003c 2.12.5"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-190",
              "description": "CWE-190: Integer Overflow or Wraparound",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-25T19:36:36.370Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6"
        },
        {
          "name": "https://advisories.nats.io/CVE/secnote-2026-03.txt",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://advisories.nats.io/CVE/secnote-2026-03.txt"
        }
      ],
      "source": {
        "advisory": "GHSA-pq2q-rcw4-3hr6",
        "discovery": "UNKNOWN"
      },
      "title": "NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27889",
    "datePublished": "2026-03-25T19:36:36.370Z",
    "dateReserved": "2026-02-24T15:19:29.716Z",
    "dateUpdated": "2026-03-25T20:06:31.897Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

Vulnerability from bitnami_vulndb

CVE-2026-27889 (GCVE-0-2026-27889)

Tags

Sightings

Nomenclature