CVE-2026-34078criticalCWE-59CWE-61

CVE-2026-34078: critical vulnerability in flatpak

Flatpak has a complete sandbox escape leading to host file access and code execution in the host context

Published · Updated

Follow this CVE+ Monitor flatpak+ Monitor flatpak

E-mail alert when it lands in KEV, gets a public PoC or its score goes up.

28Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 9.3epss 1.7%
In short

Flatpak's sandbox protection can be bypassed by tricking it into mounting arbitrary host files through specially crafted symlinks, allowing an app to access any file on the system and execute code with full system privileges.

Technical detail

CWE-61 symlink following vulnerability in Flatpak portal: sandbox-expose options accept app-controlled symlinks that resolve to arbitrary host paths; portal mounts the resolved paths into sandbox without proper validation, enabling arbitrary host file access and code execution in host context. Affected versions prior to 1.16.4.

Summary generated and translated by AI from the official description.
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.
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
Affected products
flatpak · flatpak
Related CVEs — flatpak

In the same product, most dangerous first.

CVE-2022-21682HIGHflatpak-builder can access files outside the build directory.EPSS 1.8%CVE-2021-21381HIGHSandbox escape via special tokens in .desktop fileEPSS 1.5%CVE-2021-43860HIGHPermissions granted to applications can be hidden from the user at install timeEPSS 1.4%CVE-2024-42472CRITICALFlatpak may allow access to files outside sandbox for certain appsEPSS 1.3%CVE-2023-28101MEDIUMFlatpak metadata with ANSI control codes can cause misleading terminal outputEPSS 0.9%CVE-2023-28100CRITICALTIOCLINUX can send commands outside sandbox if running on a virtual consoleEPSS 0.9%