Copier safe template has filesystem write access outside destination path_CVE-2025-55214

{
    "lastseen": "",
    "description": "Copier library and CLI app for rendering project templates. From 7.1.0 to before 9.9.1, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the --UNSAFE,--trust flag. As it turns out, a safe template can currently write files outside the destination path where a project shall be generated or updated. This is possible when rendering a generated directory structure whose rendered path is either a relative parent path or an absolute path. Constructing such paths is possible using Copier's builtin pathjoin Jinja filter and its builtin _copier_conf.sep variable, which is the platform-native path separator. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. This vulnerability is fixed in 9.9.1.",
    "published": "2025-08-18T16:36:46.621Z",
    "modified": "2025-08-18T16:36:46.621Z",
    "type": "cve",
    "title": "Copier safe template has filesystem write access outside destination path",
    "source": "GitHub_M",
    "references": "https://github.com/copier-org/copier/security/advisories/GHSA-p7q8-grrj-3m8w\nhttps://github.com/copier-org/copier/commit/fdbc0167cc22780b497e4db176feaf6f024757d6",
    "id": "CVE-2025-55214",
    "bulletinFamily": "",
    "cwe": [
        "CWE-22"
    ],
    "cvelist": null,
    "sourceData": "copier-org copier >= 7.1.0, < 9.9.1",
    "sourceHref": "",
    "cvss": {
        "score": 6.9,
        "severity": "MEDIUM",
        "vector": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
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        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "copier",
    "version": ">= 7.1.0, < 9.9.1",
    "vendor": "copier-org",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
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    "ai_score": 0
}