CVE-2026-90616 Path traversal in Flatpak
A malicious sandboxed app can exploit missing symlink protection to access host files and execute arbitrary code on the host system.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90616?
CVE-2026-90616 is a high-severity path traversal vulnerability in Flatpak, published on 12 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.
Weakness: CWE-61
Which versions are affected by CVE-2026-90616?
How do I fix CVE-2026-90616?
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-2026-90616 being exploited?
There is no known exploitation of CVE-2026-90616 in the wild and no public exploit code.
Sources
Also known as CLSA-2026-1789577977, CLSA-2026-1789979782, CLSA-2026-1790035964, DEBIAN-CVE-2026-90616, GHSA-8688-9x26-hhxj, GHSA-vhx5-8pfj-7wrv and 2 more.