{"id":"CVE-2026-39977","summary":"flatpak-builder has a path traversal leading to arbitrary file read on host when installing licence files","details":"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.","aliases":["GHSA-6gm9-3g7m-3965"],"modified":"2026-08-12T03:51:14.408175156Z","published":"2026-04-09T19:05:23.616Z","related":["openSUSE-SU-2026:10590-1"],"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":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39977.json"},{"type":"ADVISORY","url":"https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-6gm9-3g7m-3965"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39977"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/flatpak/flatpak-builder","events":[{"introduced":"ed24fdee5add29cdeed2577512282f5a356cace5"},{"fixed":"70421c1586e9046470c9a788fa3f3390d5431248"}],"database_specific":{"extracted_events":[{"introduced":"1.4.5"},{"fixed":"1.4.8"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:flatpak:flatpak-builder:*:*:*:*:*:*:*:*"}}],"versions":["1.4.7","1.4.6","1.4.5"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39977.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}