« Volver al listado

CVE-2026-55996

Estado: Pendiente de análisisMedia (4.3)—

A denial-of-service vulnerability was identified in multiple TLS listeners in Rancher. Both the cattle-cluster-agent component running in downstream clusters and the Rancher server itself use the dynamiclistener library to serve TLS traffic. Without an effective CN filter configured, dynamiclistener automatically appended to each serving certificate any hostname presented via Server Name Indication (SNI) in incoming TLS requests.

An unauthenticated attacker with network access within the affected cluster could send a large number of TLS requests with distinct hostnames, causing the serving certificate to accumulate an unbounded number of Subject Alternative Names (SANs).

Leer descripción completaMostrar menos

Eventually, the certificate grows large enough that TLS handshakes fail with an excessive message size error, causing a denial of service on the affected listeners.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (3)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Rancher — Cattle-cluster-agentAIRancher — DynamiclistenerAIRancher — RancherAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-55996",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55996",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-05T13:40:18.178968Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "meissner@suse.de",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "meissner@suse.de",
      "affectedData": [
        {
          "vendor": "SUSE",
          "product": "Rancher",
          "versions": [
            {
              "status": "affected",
              "version": "2.11.0",
              "lessThan": "2.11.16",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "2.12.0",
              "lessThan": "2.12.12",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "2.13.0",
              "lessThan": "2.13.8",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "2.14.0",
              "lessThan": "2.14.4",
              "versionType": "semver"
            }
          ],
          "packageName": "Rancher",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-08-05T08:16:34.173",
  "references": [
    {
      "url": "https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-55996",
      "source": "meissner@suse.de"
    },
    {
      "url": "https://github.com/rancher/rancher/security/advisories/GHSA-9jxv-832x-45q9",
      "source": "meissner@suse.de"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A denial-of-service vulnerability was identified in multiple TLS listeners in Rancher. Both the cattle-cluster-agent component running in downstream clusters and the Rancher server itself use the dynamiclistener library to serve TLS traffic. Without an effective CN filter configured, dynamiclistener automatically appended to each serving certificate any hostname presented via Server Name Indication (SNI) in incoming TLS requests.\n\n\n\nAn unauthenticated attacker with network access within the affected cluster could send a large number of TLS requests with distinct hostnames, causing the serving certificate to accumulate an unbounded number of Subject Alternative Names (SANs). Eventually, the certificate grows large enough that TLS handshakes fail with an excessive message size error, causing a denial of service on the affected listeners."
    }
  ],
  "lastModified": "2026-09-01T20:54:51.287",
  "sourceIdentifier": "meissner@suse.de"
}