PT-2026-31705 · Unknown · Flatpak-Builder

CVE-2026-39977 · Published 2026-04-09 · Updated 2026-04-21

Positive Technologies (AI Summary)

CVSS v4.0

7.1

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions flatpak-builder versions 1.4.5 through 1.4.7

Description flatpak-builder, a tool for building flatpaks from source, contains a flaw where the 'license-files' manifest key can be exploited to read arbitrary files from the host system and include them in the build output. This occurs because the validation of file paths does not fully resolve symlinks, allowing a crafted manifest and/or source to bypass security checks. The issue affects versions from 1.4.5 up to, but not including, 1.4.8.

Recommendations Update to flatpak-builder version 1.4.8 or later.

Exploit

Fix

Path traversal

Weakness Enumeration

CWE-22

Related Identifiers

CVE-2026-39977

GHSA-6GM9-3G7M-3965

OPENSUSE-SU-2026:10590-1

Affected Products

Flatpak-Builder

References · 12

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39977.json · Exploit
• https://github.com/flatpak/flatpak-builder/security/advisories/GHSA-6gm9-3g7m-3965 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-39977 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-39977 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-39977 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-39977 · Security Note
• https://ubuntu.com/security/CVE-2026-39977 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:10590-1 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-39977 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-39977 · Vendor Advisory
• https://suse.com/security/cve/CVE-2026-39977 · Note
• https://twitter.com/CVEnew/status/2042340069260882241 · Twitter Post