CVE-2026-34078 CRITICAL

CVE-2026-34078: Flatpak has a complete sandbox escape leading to host file access and code execution in the host context

Vendor Flatpak
Product flatpak
Weakness CWE-61
Published April 7, 2026
Last update June 30, 2026
View on NVD All CVEs

CVSS base score

9.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Flatpak is a Linux application sandboxing and distribution framework. Prior to 1.16.4, the Flatpak portal accepts paths in the sandbox-expose options which can be app-controlled symlinks pointing at arbitrary paths. Flatpak run mounts the resolved host path in the sandbox. This gives apps access to all host files and can be used as a primitive to gain code execution in the host context. This vulnerability is fixed in 1.16.4.

Key dates

02Disclosure timeline

April 7, 2026 CVE published
June 30, 2026 Record updated