CVE-2026-34078 Flatpak has a complete sandbox escape leading to host file access and code execution in the host context
Attackers can escape the Flatpak sandbox to access host files and execute code on the host system via symlink manipulation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34078?
CVE-2026-34078 is a critical path traversal vulnerability in flatpak, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Which versions are affected by CVE-2026-34078?
It affects 1 product.
Products include Flatpak Flatpak.
How do I fix CVE-2026-34078?
Upgrade to a fixed version.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-34078 being exploited?
There is no known exploitation of CVE-2026-34078 in the wild and no public exploit code.
Other vulnerabilities in flatpak
- CVE-2023-28100 TIOCLINUX can send commands outside sandbox if running on a virtual console
- CVE-2019-10063 Security feature bypass in n/a
- CVE-2018-6560 Security feature bypass in n/a
- CVE-2026-34079 Flatpak affected by arbitrary file deletion on the host filesystem
- CVE-2023-28101 Flatpak metadata with ANSI control codes can cause misleading terminal output
Sources
Also known as CLSA-2026-1780908222, CLSA-2026-1781603962, CLSA-2026-1792427048, CLSA-2026-1792427434, DEBIAN-CVE-2026-34078, GHSA-cc2q-qc34-jprg and 1 more.