{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "9.5.0"
              },
              {
                "fixed": "9.15.2"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "d735c8beac8307c06d9c881714328b76711a4b4d"
            },
            {
              "fixed": "a90729e8b828ccfdd4e066696044ac20a85be81c"
            }
          ],
          "repo": "https://github.com/copier-org/copier",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-9gmc-jqmh-3rvm"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-22",
      "CWE-94"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53951.json"
  },
  "details": "Copier is a library and CLI app for rendering project templates. In versions 9.5.0 through 9.15.1, the `trust` setting's prefix match\n(`copier/_settings.py`) compares the template URL against a trusted prefix with a raw `str.startswith` and no path normalization, while the URL is normalized when the template is actually fetched (`Path.resolve()` for local paths; libcurl dot-segment removal for `https`). A template reference that textually starts with a trusted prefix but contains `..` is therefore granted trust yet resolves to a different, attacker-controlled template, whose `tasks` / `migrations` / `jinja_extensions` then run without the `--trust` prompt — arbitrary command execution. Version 9.15.2 patches the issue.",
  "id": "CVE-2026-53951",
  "modified": "2026-08-12T03:51:15.795024734Z",
  "published": "2026-07-08T15:26:08.626Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/copier-org/copier/releases/tag/v9.15.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53951.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/copier-org/copier/security/advisories/GHSA-9gmc-jqmh-3rvm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53951"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Copier: trust-prefix bypass via path traversal runs tasks unprompted"
}