FKIE_CVE-2026-66897

Vulnerability from fkie_nvd - Published: 2026-08-24 10:16 - Updated: 2026-10-24 16:10
Severity
9.9 (Critical) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root. When processing target template paths specified in metadata.yaml, LXD validates the path against a confined os.Root directory handle but subsequently opens and creates the file using os.Create with an unconfined string path. This discrepancy between path resolution checks and file creation allows an attacker to escape directory confinement, overwrite root-owned host files, and achieve host root code execution.
References
security@ubuntu.comhttps://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fvVendor Advisory, Exploit
Impacted products
Vendor Product Version
canonical lxd *
canonical lxd *
canonical lxd *
canonical lxd *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageName": "LXD",
          "platforms": [
            "Linux"
          ],
          "product": "LXD",
          "repo": "https://github.com/canonical/lxd",
          "vendor": "Canonical",
          "versions": [
            {
              "lessThan": "4.0.13",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.0.9",
              "status": "affected",
              "version": "5.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "5.21.7",
              "status": "affected",
              "version": "5.21.0",
              "versionType": "semver"
            },
            {
              "lessThan": "6.10",
              "status": "affected",
              "version": "6.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@ubuntu.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "C0F22A55-5146-4B91-9D3E-BC4509F506BE",
              "versionEndExcluding": "4.0.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "5DE002EB-DEFA-4284-A2C5-F68C71B121DF",
              "versionEndExcluding": "5.0.9",
              "versionStartIncluding": "5.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "84E5D160-5D14-4E78-AEDD-E9906420FB2E",
              "versionEndExcluding": "5.21.7",
              "versionStartIncluding": "5.1",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "372FD242-9957-420D-BDDC-D4C81BB996D4",
              "versionEndIncluding": "6.9",
              "versionStartIncluding": "6.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "A path traversal vulnerability in LXD\u0027s instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root. When processing target template paths specified in metadata.yaml, LXD validates the path against a confined os.Root directory handle but subsequently opens and creates the file using os.Create with an unconfined string path. This discrepancy between path resolution checks and file creation allows an attacker to escape directory confinement, overwrite root-owned host files, and achieve host root code execution."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de salto de ruta en el procesamiento de plantillas de instancia de LXD permite a un atacante con permisos de edici\u00f3n de contenedor, o a cualquier usuario que inicie una imagen manipulada, sobrescribir archivos arbitrarios en el sistema anfitri\u00f3n como root. Al procesar rutas de plantilla de destino especificadas en metadata.yaml, LXD valida la ruta contra un manejador de directorio os.Root confinado, pero posteriormente abre y crea el archivo usando os.Create con una ruta de cadena no confinada. Esta discrepancia entre las comprobaciones de resoluci\u00f3n de ruta y la creaci\u00f3n de archivos permite a un atacante escapar del confinamiento de directorio, sobrescribir archivos del anfitri\u00f3n propiedad de root y lograr la ejecuci\u00f3n de c\u00f3digo root en el anfitri\u00f3n."
    }
  ],
  "id": "CVE-2026-66897",
  "lastModified": "2026-10-24T16:10:00.153",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.9,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 6.0,
        "source": "security@ubuntu.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-66897",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-24T00:00:00+00:00",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-24T10:16:39.767",
  "references": [
    {
      "source": "security@ubuntu.com",
      "tags": [
        "Vendor Advisory",
        "Exploit"
      ],
      "url": "https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fv"
    }
  ],
  "sourceIdentifier": "security@ubuntu.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        },
        {
          "lang": "en",
          "value": "CWE-23"
        }
      ],
      "source": "security@ubuntu.com",
      "type": "Secondary"
    }
  ]
}



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