Directory Traversal Affecting flatpak-builder package, versions <1.4.8-1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.29% (21st percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-FLATPAKBUILDER-15998325
  • published13 Apr 2026
  • disclosed9 Apr 2026

Introduced: 9 Apr 2026

CVE-2026-39977  (opens in a new tab)
CWE-22  (opens in a new tab)

How to fix?

Upgrade Debian:unstable flatpak-builder to version 1.4.8-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream flatpak-builder package and not the flatpak-builder package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1