CVE-2026-34078
—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.
- Vendors
- flatpak
- Products
- flatpak
- Weakness
- CWE-61, CWE-59
- 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/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
In the news3 stories
USN-8741-1: Flatpak vulnerabilities
Ubuntu patched two Flatpak flaws, including a sandbox escape via app-controlled symlinks allowing host code execution (CVE-2026-34078).
Ubuntu security notice USN-8741-1 fixes two Flatpak vulnerabilities in Ubuntu 20.04 LTS, 22.04 LTS, and 24.04 LTS. CVE-2026-34078 stems from improper path validation in sandbox-expose options, letting a malicious or compromised Flatpak app use app-controlled symlinks to access arbitrary host files and gain code execution in the host context. CVE-2026-34079 involves improper path validation when removing outdated ld.so cache files, allowing a compromised app to delete arbitrary files on the host.