CVE-2026-39977
flatpak-builder has a path traversal leading to arbitrary file read on host when installing licence files
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.
| CWE | CWE-22 |
| Vendor | flatpak |
| Product | flatpak-builder |
| Published | Apr 9, 2026 |
| Last Updated | Apr 9, 2026 |
Get instant alerts for flatpak flatpak-builder
Be the first to know when new unknown vulnerabilities affecting flatpak flatpak-builder are published — delivered to Slack, Telegram or Discord.