CVE-2026-96276 Flatpak: flatpak: arbitrary write in host context via flatpak build-init
A malicious SDK can write arbitrary files to the host system during flatpak build-init, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-96276?
CVE-2026-96276 is a medium-severity path traversal vulnerability in Red Hat Enterprise Linux 10, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
If a malicious SDK container declares an extension point with a crafted `directory` path, and a developer runs `flatpak build-init --writable-sdk --sdk-extension` with that SDK, attacker-chosen files could be written outside the working directory, since the target path is resolved via a function that allows `..` traversal.
Weakness: CWE-22
Which versions are affected by CVE-2026-96276?
How do I fix CVE-2026-96276?
Apply the vendor's patch.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-96276 being exploited?
There is no known exploitation of CVE-2026-96276 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-96276, UBUNTU-CVE-2026-96276.