Ad

CVE-2026-39977

HIGH CVSS 4.0: 7.1 EPSS 0.02%
Updated Apr 16, 2026
Flatpak
Parameter Value
CVSS 7.1 (HIGH)
Affected Versions 1.4.5 — 1.4.8
Fixed In 1.4.8
Type CWE-22 (Path Traversal)
Vendor Flatpak
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Flatpak Flatpak-Builder
cpe:2.3:a:flatpak:flatpak-builder:*:*:*:*:*:*:*:*
1.4.5 1.4.8

Related Vulnerabilities