Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root

{
  "id": "58693f3aa77b4cd5f483cb16ae20d5745ef10beb5f3e55b5e3205e5bb35b5391",
  "url": "https://osv.dev/vulnerability/CVE-2026-63343",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root",
    "summary": "Incus is a system container and virtual machine manager. Prior to version 7.3.0, a malicious image containing a `metadata.yaml` symlink pointing to an arbitrary host path allows an authenticated Incus user to read or overwrite any file on the host as root via the instance metadata API. The `exec-output` and `templates/` paths were patched in a prior release using `Lstat` rejection and `os.OpenRoot` confinement; `metadata.yaml` was not included in either patch and remains exploitable. Version 7.3.0 patches the issue.",
    "evidence": "osv:CVE-2026-63343",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-63343",
      "aliases": [
        "CVE-2026-63343",
        "GHSA-fmjx-5j3g-997p"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/lxc/incus",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "90429bf42f08b41c091e799d81465ff24b5cee2b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "7.3.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "7.3.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v7.2.0",
            "v7.0.0",
            "v7.1.0",
            "v6.23.0",
            "v6.22.0",
            "v6.21.0",
            "v6.20.0",
            "v6.19.1",
            "v6.19.0",
            "v6.18.0",
            "v6.17.0",
            "v6.16.0",
            "v6.14.0",
            "v6.15.0",
            "v6.13.0",
            "v6.12.0",
            "v6.11.0",
            "v6.10.1",
            "v6.10.0",
            "v6.9.0",
            "v6.8.0",
            "v6.7.0",
            "v6.6.0",
            "v6.5.0",
            "v6.4.0",
            "v6.3.0",
            "v6.2.0",
            "v6.0.0",
            "v6.1.0",
            "v0.7.0",
            "v0.6.0",
            "v0.5.1",
            "v0.5.0",
            "v0.4.0",
            "v0.3.0",
            "v0.2.0",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63343.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:24.972767226Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63343.json",
        "https://github.com/lxc/incus/security/advisories/GHSA-fmjx-5j3g-997p",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-63343"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-73"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63343.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-63343",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491506,
  "published_at": "2026-08-21T14:53:26.109+00:00"
}