CVE-2026-39977

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.

Database specific

{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-22"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39977.json"
}

References

Affected packages

Git / github.com/flatpak/flatpak-builder

Affected ranges

Type

GIT

Repo

https://github.com/flatpak/flatpak-builder

Events

Introduced

ed24fdee5add29cdeed2577512282f5a356cace5

Fixed

70421c1586e9046470c9a788fa3f3390d5431248

Database specific

Show details

{
    "cpe": "cpe:2.3:a:flatpak:flatpak-builder:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "1.4.5"
        },
        {
            "fixed": "1.4.8"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ]
}

Affected versions

1.*

1.4.5

1.4.6

1.4.7

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39977.json"