FKIE_CVE-2026-66897

Vulnerability from fkie_nvd - Published: 2026-08-24 10:16 - Updated: 2026-08-25 04:18
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-8fx9-42fv
Impacted products
Vendor Product Version
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"
    }
  ],
  "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."
    }
  ],
  "id": "CVE-2026-66897",
  "lastModified": "2026-08-25T04:18:15.863",
  "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",
      "url": "https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fv"
    }
  ],
  "sourceIdentifier": "security@ubuntu.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        },
        {
          "lang": "en",
          "value": "CWE-23"
        }
      ],
      "source": "security@ubuntu.com",
      "type": "Secondary"
    }
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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