Dashboard / CVE-2026-39977

CVE-2026-39977

HIGH
MEDIUM Priority: 0.02 BB Relevance: 64/100
Published: 2026-04-09 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth Conf. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Passive
S: X
AT: None
VC: High
VI: None
VA: None

Description

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
flatpak flatpak-builder 1.4.5 – 1.4.8

References & Advisories (1)

Bug Bounty Relevance

64 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

7.1 / 10.0 v4.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.29%
Raw Score 0.002880
Percentile 21.3%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00288
2026-10-28
0.00288

Intelligence Sources

nvd ref →

External Links