flatpak-builder has a path traversal leading to arbitrary file read on host when installing licence files_CVE-2026-39977

{
    "lastseen": "",
    "description": "flatpak-builder is a tool to build flatpaks from source. From 1.4.5 to before 1.4.8, the license-files manifest key takes an array of paths to user defined licence files relative to the source directory of the module. The paths from that array are resolved using g_file_resolve_relative_path() and validated to stay inside the source directory using two checks - g_file_get_relative_path() which does not resolve symlinks and g_file_query_file_type() with G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS which only applies to the final path component. The copy operation runs on host. This can be exploited by using a crafted manifest and/or source to read arbitrary files from the host and capture them into the build output. This vulnerability is fixed in 1.4.8.",
    "published": "2026-04-09T19:05:23.616Z",
    "modified": "2026-04-09T20:19:28.323Z",
    "type": "cve",
    "title": "flatpak-builder has a path traversal leading to arbitrary file read on host when installing licence files",
    "source": "GitHub_M",
    "references": "https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-6gm9-3g7m-3965",
    "id": "CVE-2026-39977",
    "bulletinFamily": "",
    "cwe": [
        "CWE-22"
    ],
    "cvelist": null,
    "sourceData": "flatpak flatpak-builder >= 1.4.5, < 1.4.8",
    "sourceHref": "",
    "cvss": {
        "score": 7.1,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "flatpak-builder",
    "version": ">= 1.4.5, < 1.4.8",
    "vendor": "flatpak",
    "ai_description": "",
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    "ai_score": 0
}