CVE-2026-96808 Path traversal in Flatpak
A local attacker can exploit symlink traversal in Flatpak's revokefs writer to modify system repository files and escalate privileges to root.
- 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-2026-96808?
CVE-2026-96808 is a high-severity path traversal vulnerability in Flatpak, published on 23 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, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper. In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation.
Weakness: CWE-61
Which versions are affected by CVE-2026-96808?
How do I fix CVE-2026-96808?
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-2026-96808 being exploited?
There is no known exploitation of CVE-2026-96808 in the wild and no public exploit code.
Sources
Also known as CLSA-2026-1790844951, CLSA-2026-1791735799, DEBIAN-CVE-2026-96808, GHSA-qrwq-7qwx-q9rp, OESA-2026-4569, OESA-2026-4571 and 1 more.