FKIE_CVE-2026-33219

Vulnerability from fkie_nvd - Published: 2026-03-25 20:16 - Updated: 2026-03-25 20:16
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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, a malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-27571. That earlier issue was a compression bomb, this vulnerability is not. Attacks against this new issue thus require significant client bandwidth. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable websockets if not required for project deployment.
References
security-advisories@github.comhttps://advisories.nats.io/CVE/secnote-2026-02.txt
security-advisories@github.comhttps://advisories.nats.io/CVE/secnote-2026-11.txt
security-advisories@github.comhttps://github.com/advisories/GHSA-qrvq-68c2-7grw
security-advisories@github.comhttps://github.com/nats-io/nats-server/security/advisories/GHSA-8r68-gvr4-jh7j
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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, a malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-27571. That earlier issue was a compression bomb, this vulnerability is not. Attacks against this new issue thus require significant client bandwidth. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable websockets if not required for project deployment."
    }
  ],
  "id": "CVE-2026-33219",
  "lastModified": "2026-03-25T20:16:32.777",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "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:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-25T20:16:32.777",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://advisories.nats.io/CVE/secnote-2026-02.txt"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://advisories.nats.io/CVE/secnote-2026-11.txt"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/advisories/GHSA-qrvq-68c2-7grw"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-8r68-gvr4-jh7j"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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